ANSI-AGMA 6114-A06

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ANSI/AGMA 6114-A06
[Metric Edition of
ANSI/AGMA 6014--A06]
AMERICAN NATIONAL STANDARD
Gear Power Rating for Cylindrical Shell
and Trunnion Supported Equipment
(Metric Edition)
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ii
GearPowerRating forCylindrical Shell andTrunnionSupportedEquipment
(Metric Edition)
ANSI/AGMA 6114--A06
(Metric Edition of ANSI/AGMA 6014--A06)
Approval of an AmericanNational Standard requires verification by ANSI that the require-
ments for due process, consensus, and other criteria for approval have been met by the
standards developer.
Consensus is established when, in the judgment of the ANSI Board of Standards Review,
substantial agreement has been reached by directly and materially affected interests.
Substantial agreementmeansmuchmore than a simplemajority, but not necessarily una-
nimity. Consensus requires that all views and objections be considered, and that a
concerted effort be made toward their resolution.
The use of AmericanNational Standards is completely voluntary; their existence does not
in any respect preclude anyone, whether he has approved the standards or not, from
manufacturing, marketing, purchasing, or using products, processes, or procedures not
conforming to the standards.
The American National Standards Institute does not develop standards and will in no
circumstances give an interpretation of any American National Standard. Moreover, no
person shall have the right or authority to issue an interpretation of an American National
Standard in the nameof theAmericanNational Standards Institute. Requests for interpre-
tation of this standard should be addressed to the American Gear Manufacturers
Association.
CAUTION NOTICE: AGMA technical publications are subject to constant improvement,
revision, or withdrawal as dictated by experience. Any person who refers to any AGMA
technical publication should be sure that the publication is the latest available from theAs-
sociation on the subject matter.
[Tables or other self--supporting sections may be referenced. Citations should read: See
ANSI/AGMA 6114--A06,Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition), published by the American Gear Manufacturers Association,
500 Montgomery Street, Suite 350, Alexandria, Virginia 22314, http://www.agma.org.]
Approved September 29, 2006
ABSTRACT
This standard specifies a method for rating the pitting resistance and bending strength of open or semi--
enclosed spur, single helical, double helical, and herringbone gears made from steel and spheroidal graphitic
iron for use on cylindrical shell and trunnion supported equipment such as cylindrical grindingmills, kilns, cool-
ers and dryers. Annexes cover installation, alignment,maintenance, lubrication, and a ratingmethod for gears
made from ausferritic ductile iron.
Published by
American Gear Manufacturers Association
500 Montgomery Street, Suite 350, Alexandria, Virginia 22314
Copyright © 2006 by American Gear Manufacturers Association
All rights reserved.
No part of this publication may be reproduced in any form, in an electronic
retrieval system or otherwise, without prior written permission of the publisher.
Printed in the United States of America
ISBN: 1--55589--877--7
American
National
Standard
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
iii© AGMA 2006 ---- All rights reserved
Contents
Page
Foreword v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Scope 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Normative references 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Definitions and symbols 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Application 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Criteria for tooth capacity 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 Rating formulas 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 Geometry factors, ZI and YJ 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 Dynamic factor, Kvm 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 Elastic coefficient, ZE 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Service factor 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 Hardness ratio factor, ZW 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 Load distribution factor, KH 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 Allowable stress numbers, σHP and σFP 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14 Momentary overloads 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 Stress cycle factors, ZN and YN 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bibliography 71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Annexes
A New equipment installation and alignment 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B Drive characteristics -- Multiple pinion drives 35. . . . . . . . . . . . . . . . . . . . . . . . . . .
C Rim thickness/deflection 38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D Open gearing lubrication 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
E Sample problems 44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
F Material mechanical properties 58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G Operation and maintenance 59. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
H Ausferritic ductile iron (ADI) 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I Service factors 67. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
J Method for determination of dynamic factor with AGMA 2000--A88 69. . . . . . . .
Figures
1 Rim thickness factor, KBm 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Dynamic factor, Kvm 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Hardness ratio factor, ZW 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Pinion proportion factor, KHpf 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Mesh alignment factor, KHma 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 Allowable contact stress number for through hardened steel gears, σHP 18. . .
7 Allowable bending stress number for through hardened steel gears, σFP 18. . .
8 Allowable contact stress number for spheroidal graphitic iron gears, σHP 19. .
9 Allowablebending stress number for spheroidal graphitic iron gears, σFP 19. .
10 Hardening pattern obtainable on pinion teeth with induction hardening 30. . . .
11 Minimum effective case depth for carburized and induction hardened
pinions, he min 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 Steel and spheroidal graphitic iron pitting resistance stress cycle
factor, ZN 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 Steel and spheroidal graphitic iron bending strength stress cycle
factor, YN 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
iv © AGMA 2006 ---- All rights reserved
Tables
1 Symbols and definitions 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Empirical constants: A, B, and C 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Allowable contact stress number, σHP, for steel and spheroidal graphitic
iron gears 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Allowable bending stress number, σFP, for steel and spheroidal graphitic
iron gears 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Metallurgical characteristics for steel pinions and gears 20. . . . . . . . . . . . . . . . .
6 Metallurgical characteristics for spheroidal graphitic iron gears 23. . . . . . . . . . .
7 Metallurgical characteristics for wrought carburized and hardened pinions 24.
8 Metallurgical characteristics for wrought induction hardened pinions 27. . . . . .
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
v© AGMA 2006 ---- All rights reserved
Foreword
[The foreword, footnotes and annexes, if any, in this document are provided for
informational purposes only and are not to be construed as a part of AGMA Standard
6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported Equipment
(Metric Edition).]
This standard presents formulas and information using ISO symbology and SI units.
AGMA 321.01 was originally developed to cover gears used primarily for ball and rodmills,
and for kilns and dryers. It was approved in October 1943, and later modified in June 1946.
In June 1951, AGMA 321.03 was approved as a standard. Further changes and additions
were approved in June 1959, and AGMA321.04was issued inMarch 1960. AGMA321.05
was approved in March 1968 and issued in March 1970.
In February 1979, themill gearing committeewas reorganized to reviewAGMA321.05 and
revise it in accordance with AGMA 218.01, Rating the Pitting Resistance and Bending
Strength of Spur and Helical Involute Gear Teeth. With AGMA 218.01 as a guide, the
committee submitted the first draft of ANSI/AGMA 6004--F88 in March 1984.
ANSI/AGMA 6004--F88 superseded AGMA 321.05, Design Practice for Helical and
Herringbone Gears for Cylindrical Grinding Mills, Kilns, Coolers, and Dryers. It was
approved by the AGMA membership in January 1988 and approved as an American
National Standard on May 31, 1988.
ANSI/AGMA 6004 was not widely accepted by the industry and many continued to use
AGMA 321.05. As such, the AGMAMill Gearing began work on ANSI/AGMA 6114--A06 in
November 2001. Changes to the standard include a new dynamic factor analysis as a
function of transmission accuracy number, revised allowable stress numbers, theuseof the
stress cycle factor in the rating practice, and ratings for gears made from spheroidal
graphitic iron. Extensive discussions on new equipment installation and alignment,
lubrication, and use of ausferritic ductile iron were added to the annex.
Values for factors assigned in previous standards are not applicable to this Standard, nor
are the values assigned in this Standard applicable to previous standards. The ability to
design gears, and the knowledge and judgment required to properly evaluate the various
rating factors comes primarily from years of accumulated experience in gearing. The
detailed treatment of the general rating formulas for specific applications is best
accomplished by those experienced in the field.
ANSI/AGMA 6114--A06 supersedes ANSI/AGMA 6004--F88, Gear Power Rating for
Cylindrical Grinding Mills, Kilns, Coolers and Dryers. The first draft of ANSI/AGMA
6114--A06 was made in November, 2001. It was approved by the AGMA membership in
July 2006 and approved as an American National Standard on September 29, 2006.
Suggestions for improvement of this standard will be welcome. They should be sent to the
AmericanGearManufacturersAssociation, 500MontgomeryStreet,Suite 350,Alexandria,
Virginia 22314.
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
vi © AGMA 2006 ---- All rights reserved
PERSONNEL of the AGMA Mill Gearing Committee
Chairman: Craig Danecki Rexnord Industries, LLC. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vice Chairman: Gary A. Bish Horsburgh & Scott Company. . . . . . . . . . . . . . . . . . . . . . . . .
ACTIVE MEMBERS
J.C. Berney--Ficklin Bechtel Corporation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
J. Carr FLSmidth & Company. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
J.L. Daubert FLSmidth & Company. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
M. Dreher Ferry--Capitain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T.C. Glasener Xtek, Incorporated. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
R.W. Hankes A--C Equipment Services Corporation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
E.O. Hurtado FFE Minerals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
M.J. Raab Anderol, Inc.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V. Svalbonas Metso Minerals, Ltd.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Y. Theberge Metso Minerals, Ltd.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
F.C. Uherek Rexnord Industries, LLC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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1© AGMA 2006 ---- All rights reserved
ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
American National Standard --
Gear Power Rating for
Cylindrical Shell and
Trunnion Supported
Equipment (Metric
Edition)
1 Scope
1.1 Applicability
This standard provides a methodto determine the
power ratingof gear sets for cylindrical grindingmills,
kilns, coolers, and dryers. The formulas are
applicable to steel and spheroidal graphitic iron
gears with machined spur, single helical, double
helical, or herringbone gear teeth commonly used
for this purpose. Calculations determine the allow-
able rating for pitting resistance and bending
strength of external spur and helical involute gear
teeth.
1.2 Rating formulas
This standard provides a method by which different
gear designs can be rated and compared. It is not
intended to assure the performance of assembled
gear drive systems.
These rating formulas are applicable for rating the
pitting resistance and bending strength of external
spur and helical involute gear teeth operating on
parallel axes with adjustable center distances. The
formulas evaluate gear tooth capacity as influenced
by the major factors which affect gear tooth pitting
and gear tooth fracture at the fillet radius.
This standard is intended for use by experienced
gear designers, capable of selecting reasonable
values for the rating factors. It is not intended for use
by the engineering public at large.
Values for factors assigned in other standards are
not applicable to this standard nor are the values
assigned in this standard applicable to other stan-
dards. Mixing values from other standards with
those from this standard could lead to erroneous
ratings.
The gear designer or manufacturer is not responsi-
ble for the total system unless such a requirement is
clearly identified in the contractual agreement.
It is imperative that the system designer be satisfied
that the system of connected rotating parts is
compatible, free from critical speeds and from
torsional or other vibrations within the specified
speed range, no matter how induced.
Where empirical values for rating factors are given
by curves, curve--fitting equations are provided to
facilitate computer programming. The constants
and coefficients used in curve fitting often have
significant digits in excess of those inferred by the
reliability of the empirical data. Experimental data
from actual gear unit measurements are seldom
repeatable within a plus or minus 10 percent band.
Calculatedgear ratings are intended to be conserva-
tive, but the scatter in actual results may exceed 20
percent.
CAUTION: Compliance with this standard does not
constitute a warranty of the rating of the gear set under
installed field service conditions.
1.3 Limitations
1) Rating procedures are limited to open or semi--
enclosed gearing where the gear reaction forces
are transmitted through a structure which pro-
vides independent bearing support for the gear
and pinion. Open gears operate without any en-
closure. Semi--enclosed gears operate with a
guard that provides some degree of protection
against contamination from dust or dirt and
retains lubricant.
2) Enclosed gear drives or speed reducers are
expressly excluded from this standard.
3) When multiple pinions are used, the number of
contacts per revolution, q, shall be the same as
the number of pinions.
4) Unless otherwise specified by contractual agree-
ment, the connected motor nameplate power in-
cluding motor service factor shall be used to
determine service factors as defined later within
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
2 © AGMA 2006 ---- All rights reserved
this standard. When not provided by the
purchaser, motor service factor equal to 1.0 shall
be used.
5) This standard does not include gearing which
has been surface hardened by nitriding or flame
hardening. This gear rating practice is limited to
through hardened steel and spheroidal graphitic
iron gears operating with through hardened,
carburized, or induction hardened steel pinions.
6) Axial contact ratio of helical gear sets, εβ, shall be
equal to or greater than 1.0.
7) Information on alignment and drive characteris-
tics is given in annexes A and B.
8) Formulas do not apply to external loads such as
dropped charges, electrical short circuits and
earthquakes.
9) Spheroidal graphitic iron data presented in the
body of the standard does not apply to austemp-
ered spheroidal graphitic iron (ADI). Rating of
ADI gearing is not covered by this standard. ADI
is discussed further in annex J.
10)This gear rating practice is limited to maximum
operating speedsof 10.2meters per secondgear
pitch line velocity.
11)This gear rating practice is limited to gears with
module of 8.0 or coarser.
1.4 Exceptions
The formulas of this standard are not applicable to
other typesof gear toothdeteriorationsuchasplastic
yielding, wear, case crushing andwelding. They are
also not applicable when vibratory conditions ex-
ceed the limits specified for the normal operation of
the gears, see ANSI/AGMA 6000--B96.
The formulas of this standard are not applicable
when any of the following conditions exist:
-- Damaged gear teeth;
-- Spur gears with transverse contact ratio, εα, less
than 1.0;
-- Spur or helical gears with transverse contact
ratio, εα, greater than 2.0;
-- Interference exists between tips of teeth and root
fillets;
-- Teeth are pointed as defined by this standard,
see clause 7;
-- Backlash is zero;
-- Undercut exists in an area above the theoretical
start of active profile;
-- The root profiles are stepped or irregular, or devi-
ate from the generated form. The YJ factor cal-
culation uses the stress concentration factors
developed by Dolan and Broghamer [1]. These
factors may not be valid for root forms which are
not smooth curves. For root profiles which are
stepped or irregular, other stress correction
factors may be more appropriate;
-- The helix angle at the standard (reference) pitch
diameter is greater than20degrees for single he-
lical and 35 degrees for double helical.
Fractures emanating from stress risers on the tooth
profile, tip chipping, and failures of the gear blank
through the web or rim should be analyzed by
general machine design methods.
2 Normative references
The following standards contain provisions which,
through reference in this text, constituteprovisionsof
this American National Standard. At the time of
publication, the editions indicated were valid. All
standards are subject to revision, and parties to
agreements based on this American National Stan-
dard are encouraged to investigate the possibility of
applying the most recent editions of the standards
indicated below.
AGMA 908--B89, Geometry Factors for Determin-
ing the Pitting Resistance and Bending Strength of
Spur, Helical and Herringbone Gear Teeth
AGMA 923--A00, Metallurgical Specifications for
Steel Gearing
ANSI/AGMA1010--E95,AppearanceofGear Teeth
– Terminology of Wear and Failure
ANSI/AGMA 1012--G05,Gear Nomenclature, Defi-
nitions of Terms with Symbols
ANSI/AGMA 2101--D04, Fundamental Rating Fac-
tors and Calculation Methods for Involute Spur and
Helical Gear Teeth
ANSI/AGMA 2004--B89, Gear Materials and Heat
Treatment Manual
ANSI/AGMA 2007--C00, Gears -- Surface Temper
Etch Inspection After Grinding
ANSI/AGMA 2015--1--A01,Accuracy Classification
System -- Tangential Measurements for Cylindrical
Gears
ANSI/AGMA 6000--B96, Specification for
Measurement of Lateral Vibration on Gear Units
ASTM A29--99, Standard Specification for Steel
Bars, Carbon and Alloy, Hot--Wrought and Cold--
Finished, General Requirements for
Copyright American Gear Manufacturers Association 
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ANSI/AGMA 6114--A06AMERICANNATIONAL STANDARD
3© AGMA 2006 ---- All rights reserved
ASTM A148--03, Specification for Steel Castings,
High Strength, for Structural Purposes
ASTM A247--67(1998), Standard Test Method for
Evaluating the Microstructure of Graphite in Iron
Castings
ASTM A255--02, Standard Test Method for Deter-
mining Hardenability of Steel
ASTMA290--02,StandardSpecification for Carbon
and Alloy Steel Forgings for Rings for Reduction
Gears
ASTM A291--03, Standard Specification for Steel
Forgings, Carbon and Alloy, for Pinions, Gears and
Shafts for Reduction Gears
ASTMA304--02,StandardSpecification for Carbon
and Alloy Steel Bars Subject to End--Quench
Hardenability Requirements
ASTM A370--03a, Standard Test Methods and
Definitions forMechanical Testing ofSteel Products
ASTM A388--01, Practice for Ultrasonic Examina-
tion of Heavy Steel Forgings
ASTM A488--04, Standard Practice for Steel Cast-
ings, Welding, Qualifications of Procedures and
Personnel
ASTM A534--01, Standard Specification for Carbu-
rizing Steels for Anti--Friction Bearings
ASTM A536--84(1999), Standard Specification for
Ductile Iron Castings
ASTM A578--96, Specification for Straight--Beam
Ultrasonic Examination of Plain and Clad Steel
Plates for Special Applications
ASTM A609--91, Practice for Castings, Carbon,
Low Alloy and Martensitic Stainless Steel,
Ultrasonic Examination Thereof
ASTM A751--01, Standard Test Methods, Practic-
es, and Terminology for Chemical Analysis of Steel
Products
ASTM A866--01, Standard Specification for
Medium Carbon Anti--Friction Bearing Steel
ASTM E8--01, Test Methods for Tension Testing of
Metallic Materials.
ASTM E45--97(2002), Standard Test Methods for
Determining the Inclusion Content of Steel
ASTM E112--96, Test Methods for Determining
Average Grain Size
ASTM E140--02, Standard Hardness Conversion
Tables for Metals -- Relationship Among Brinell
Hardness, Vickers Hardness, Rockwell Hardness,
Superficial Hardness, KnoopHardness andSclero-
scope Hardness
ASTM E351--93(2000), Standard Test Methods for
Chemical Analysis of Cast Iron -- All Types
ASTM E1019--02, Standard Test Methods for
Determination of Carbon, Sulfur, Nitrogen, and
Oxygen in Steel and in Iron, Nickel, and Cobalt
Alloys
ASTM E1444--01, Standard Practice for Magnetic
Particle Examination
AWS D1.1, Structural Welding Code as Applicable
to Cyclically Loaded Non Tubular Connections
ISO 642:1999, Steel -- Hardenability test by end
quenching (Jominy test)
ISO643:2003,Steels -- Micrographic determination
of the apparent grain size
ISO 683--1:1987,Heat treatable steels, alloy steels
and free cutting steels -- Part 1: Direct hardening
and low--alloyed wrought steel in form of different
black products
ISO 683--11--11:1987, Heat treatable steels, alloy
steels and free--cutting steels -- Part 11: Wrought
case--hardening steels
ISO 945:1975, Cast iron -- Designation of micro-
structure of graphite
ISO 1083:1987, Spheroidal graphite cast iron --
Classification
ISO 4967:1998,Steel -- Determination of content of
nonmetallic inclusions -- Micrographic method us-
ing standard diagrams
ISO 6336--5:2003, Calculation of load capacity of
spur andhelical gears -- Part 5: Strength andquality
of materials
ISO/FDIS 6336--6, Calculation of load capacity of
spur and helical gears -- Part 6: Calculation of
service life under variable load
SAE/AMS 2301, Steel Cleanliness, Aircraft Quality
Magnetic Particle Inspection Procedure
SAE/AMS--S--13165, Shot Peening of Metal Parts
SAEJ422,Microscopic Determination of Inclusions
in Steels
3 Definitions and symbols
3.1 Definitions
The symbols, terms and definitions, when applica-
ble, conform to ANSI/AGMA 1012--G05, Gear No-
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
4 © AGMA 2006 ---- All rights reserved
menclature, Definitions of Terms with Symbols, and
AGMA908--B89,Geometry Factors for Determining
thePittingResistanceandBendingStrength ofSpur,
Helical and Herringbone Gear Teeth.
Throughout the standard the terms gearing or gear
teeth can refer to either pinion or gear. The user is
cautioned to take the context of the reference under
consideration to determine if this refers to a specific
element or the mesh.
3.2 Symbols
The symbols used in the pitting resistance and
bending strength formulas are shown in table 1.
NOTE: The symbols and terminology used in this stan-
dard may differ from other AGMA standards. The user
should not assume that familiar symbols can be used
without careful study of table 1.
Table 1 -- Symbols and definitions
Symbol Description Units
Where first
used
Av Transmission accuracy number per ANSI/AGMA
2015--1--A01
-- -- Eq 6
a Operating center distance mm Eq 2
Bmill Exponential accuracy adjustment to Kvm for open gearing -- -- Eq 9
b Net face width of narrowest member mm Eq 1
Cmill Linear adjustment to Kvm for open gearing -- -- Eq 9
CSF Service factor for pitting resistance -- -- Eq 14
de Outside diameter of pinion/gear mm Eq 8
dT Tolerance diameter mm Eq 8
dw1 Operating pitch diameter of pinion mm Eq 1
E1 Modulus of elasticity for pinion N/mm2 Eq 13
E2 Modulus of elasticity for gear N/mm2 Eq 13
Fmax Maximum peak tangential load N Eq 25
Ft Transmitted tangential load N 12.2
fpt Single pitch deviation mm Eq 6
HB1 Brinell hardness of pinion HB Eq 16
HB2 Brinell hardness of gear HB Eq 16
HR1 Rockwell C hardness of pinion HRC Eq 17
he max Maximum effective case depth for external carburized and
induction hardened gear teeth
mm Eq 23
he min Minimum effective case depth for external carburized and
induction hardened gear teeth
mm Figure 11
ht Gear tooth whole depth mm Eq 5
KBm Rim thickness factor -- -- Figure 1
Kf Stress correction factor -- -- Eq 25
KH Load distribution factor -- -- Eq 1
KHe Mesh alignment correction factor -- -- Eq 19
KHma Mesh alignment factor -- -- Eq 19
KHmc Lead correction factor -- -- Eq 19
KHpf Pinion proportion factor -- -- Eq 19
KHpm Pinion proportion modifier -- -- Eq 19
KHβ Face load distribution factor -- -- Eq 18
KSF Service factor for bending strength -- -- Eq 14
Kvm Dynamic factor -- -- Eq 1
L Life hours Eq 29
mB Back--up ratio -- -- Eq 5
(continued)
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Table 1 (concluded)
Symbol Description Units
Where first
used
mn Normal module mm Eq 4
mT Transverse module mm Eq 3
nL Number of stress cycles -- -- Eq 29
P Maximum peak power kW Eq 26
Pa Allowable transmitted power for gear set kw Eq 14
Paym Allowable transmitted power for bending strength at unity
service factor
kw Eq 3
Pazm Allowable transmitted power for pitting resistance at unity
service factor
kw Eq 1
px Axial pitch mm Eq 4
Qv Transmission accuracy level number -- -- 8.2
q Number of contacts per revolution -- -- 1.3
san Normal tooth thickness at the top land of gear mm Eq 23
T Maximum transmitted pinion torque Nm Eq 26
tR Gear rim thickness mm Eq 5
u Gear ratio (never less than 1.0) -- -- Eq 2
vt Pitchline velocity at operating pitch diameter m/s Eq 9
ω Speed rpm Eq 29
ω1 Pinion speed rpm Eq 1
YJ Geometry factor for bending strength -- -- Eq 3
YN Stress cycle factor for bending strength -- -- Eq 3
ZE Elastic coefficient [N/mm2]0.5 Eq 1
ZI Geometry factor for pitting resistance -- -- Eq 1
ZN Stress cycle factor for pitting resistance -- -- Eq 1
Zw Hardness ratio factor for pitting resistance ---- Eq 15
β Helix angle at standard pitch diameter degree Eq 4
εβ Axial contact ratio -- -- 1.3
ν2 Poisson’s ratio for gear -- -- Eq 13
ν1 Poisson’s ratio for pinion -- -- Eq 13
σHP Allowable contact stress number N/mm2 Eq 1
σFP Allowable bending stress number N/mm2 Eq 3
σs Allowable yield stress number N/mm2 Eq 25
4 Application
4. 1 Manufacturing quality
Rating factors shall be selected on the basis of
expected process variations of component parts as
manufactured. The formulas of this standard are
only valid for appropriate material quality and
geometric quality that conforms to manufacturing
tolerances.
4.1.1 Geometric quality
The rating formulas of this standard are only valid if
gear tooth accuracy and gear element support
accuracy assumed in the calculations are actually
achieved in manufacture.
Flange mounted gears require that the flange of the
gear and the mounting flange of the equipment be
parallel with one another. At least one gear rim end
face should beparallel with the gearmounting flange
surfaces, or pin boss faces for spring mounted
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
6 © AGMA 2006 ---- All rights reserved
gears. That gear rim end face should be clearly
identified for alignment.
Gear tooth accuracy considerations include: invo-
lute profile, tooth alignment (lead), tooth spacing,
pitchline runout, and tooth finish.
Gear element support considerations include: as-
sembled gearmesh alignment,mounted gear flange
and rim face axial runouts, shaft pinion axial and
radial runouts, and either gear flange mount or
spring mount pin circle radial runouts, see annex A.
4.1.2 Metallurgy
Allowable stress numbers, σHP and σFP, included
herein are a function of melting, casting, forging and
heat treating practice. Allowable stress numbers in
this standard are based on 107 cycles, 99 percent
reliability, and unidirectional loading.
Allowable stressnumbersareonly valid formaterials
and conditions listed in this standard.
4.1.3 Residual stress
Residual stress in gear segments is an important
consideration. Presence of residual stress may be
checked by inspecting the gear joint assembly.
Typically this is done before finish gear cutting while
there is stock present to re--machine if the gear has
distorted, or as aminimum, after finishedmachining.
For acceptance, the joint should reassemblewithout
excessive force or misalignment. If the gear joint
cannot be satisfactorily reassembled, the gear
segments should be disassembled and
re--machined.
Anymaterial havingacase--core relationship is likely
to have residual stresses. If properly managed,
these stresses should be compressiveat the surface
and should enhance bending strength performance
of the gear teeth. Shot peening, case carburizing,
and induction hardening are common methods of
inducing compressive pre--stress in the surface of
gear teeth.
Grinding the tooth surface after heat treatment may
reduce residual compressive stresses. Incorrect
grinding of the tooth surface and root fillet area may
introduce tensile stresses or cracks in these areas.
Care must be taken to avoid excessive reduction in
hardness and changes in microstructure during the
grinding process.
4.2 Lubrication
Ratings determined by these formulas are only valid
when the gear teeth are operated with a lubricant of
proper viscosity for the load, gear tooth surface
finish, temperature, and pitchline velocity, see
annex D.
4.3 Temperature extremes
4.3.1 Cold temperature operation
When ambient temperatures are below 0°C, special
care must be given to select materials which will
have adequate impact properties at the operating
temperature. Consideration should be given to the
following:
-- low temperature Charpy specification for either
steel or spheroidal graphitic iron;
-- nil ductility temperature specification;
-- reduce carbon content of steel to less than 0.4
percent;
-- use of nickel alloy or vanadium modified steels;
-- using heating elements to increase lubricant and
gear temperatures.
4.3.2 Temperature gradient
The gear design should consider the effects of
operating temperature difference between the
mounting flange and the gear rim.
4.4 Other considerations
In addition to the factors considered in this standard
which influence pitting resistance and bending
strength, other interrelated factors can affect overall
transmissionperformance. The following factorsare
particularly significant.
4.4.1 Service damaged teeth
Formulas of this standard are only valid for undam-
aged gear teeth. Deterioration such as cracking,
plastic deformation, pitting, micropitting, wear, or
scuffing invalidate calculations of pitting resistance
and bending strength.
4.4.2 Misalignment and deflection of
foundations
Many gear systems depend on external supports
such as equipment foundations to maintain align-
ment of the gear mesh. If these supports are initially
misaligned, or are allowed to become misaligned
during operation through elastic or thermal
deflection, overall gear system performance will be
adversely affected.
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4.4.3 Deflection due to external loads
Deflection of gear supporting housings, shafts, and
bearings due to external overhung, transverse, and
thrust loads affects tooth contact across the mesh.
Since deflection varies with load, it is difficult to
obtain good tooth contact at different loads.
4.4.4 System dynamics
The dynamic response of the system results in
additional gear tooth loads due to the relative
accelerations of the connectedmassesof thedriving
and driven equipment. Overloads are a part of the
service factor which is intended to account for the
operating characteristics of the driving and driven
equipment.
However, it must be recognized that if the operating
roughness of the driving or driven equipment causes
an excitation with a frequency that is near to one of
the system’s major natural frequencies, resonant
vibrations may cause severe overloads which may
be several times higher than the nominal load. It is
recommended that a vibration analysis be per-
formed. This analysis must include the total system
of driver, driven equipment, couplings, mounting
conditions, and sources of excitation. Natural
frequencies, mode shapes, and dynamic response
amplitudes should be calculated. Responsibility for
the vibration analysis of the system rests with the
purchaser of the gearing, unless otherwise specified
by contractual agreements.
4.4.5 Corrosion
Corrosion of the gear tooth surface can have a
significant detrimental effect on the bending strength
and pitting resistance of the teeth. Quantification of
the effect of corrosion on gear teeth is beyond the
scope of this standard. Efforts should be made to
minimize corrosion and its effects.
5 Criteria for tooth capacity
5.1 Relationship of pitting resistance and
bending strength ratings
There are major differences between the pitting
resistance and bending strength ratings. Pitting is a
function of the Hertzian contact (compressive)
stresses between two cylinders and is proportional
to the square root of the applied tooth load. Bending
strength is measured in terms of the bending
(tensile) stress in a cantilever plate and is directly
proportional to this same load. The difference in
nature of the stressesinduced in the tooth surface
areas and at the tooth root is reflected in a
corresponding difference in allowable limits of con-
tact and bending stress numbers for identical
materials and load intensities.
Analysis of the load and stress modifying factors is
similar in each case, so many of these factors have
identical numerical values.
5.2 Pitting resistance
Pitting of gear teeth is considered to be a fatigue
phenomenon. Initial pitting and progressive pitting
are illustrated and discussed in ANSI/AGMA
1010--E95.
The aim of the pitting resistance formula is to
determine a load rating at which progressive pitting
of the teeth does not occur during their design life.
Ratings for pitting resistance are based on the
formulas developed by Hertz for contact pressure
between two curved surfaces,modified for the effect
of load sharing between adjacent teeth.
In most industrial applications non--progressive
initial pitting is not deemed serious on through
hardenedelements. Initial pitting is characterizedby
small pits which do not extend over the entire face
width or profile height of the effected teeth. The
definition of acceptable initial pitting varies widely
with gear application. Initial pitting occurs in
localized,overstressedareas. It tends to redistribute
the load by progressively removing high contact
spots. Generally, when the load has been reduced
or redistributed, the pitting stops.
5.3 Surface conditions not covered by pitting
resistance formula
Conditions such as micropitting, electric discharge
pitting, wear and scuffing are not covered by this
standard. See ANSI/AGMA 1010--E95 for more
information.
5.3.1 Micropitting
Micropitting is one type of gear tooth surface fatigue.
It is characterized by very small pits on the surface of
thematerial, usually less than 20micrometers deep,
that give the gear tooth the appearance of being
frosted or grey in color. This deterioration of the
surface of the material is generally thought to occur
because of influences from gear loading, material
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
8 © AGMA 2006 ---- All rights reserved
and its heat treatment, type of lubricant, and degree
of lubrication.
5.3.2 Electric discharge pitting
Electric discharge pitting is not a gear tooth rating
problem; however, it is a distressed condition of the
tooth surface. To the naked eye, the tooth surface
may not be distinguishable from micropitting as the
gear teeth exhibit a similar so--called “frosted”
appearance. It is caused by either static or stray
electricity conducted through the gear mesh due to
inappropriate electrical grounding or inappropriate
gear motor isolation. If neglected, gear failure can
occur.
5.3.3 Wear capacity of gears
Wear resistance of mating gears can be a dictating
performance limitation, particularly in these low
speed, heavily loaded gears. Gear wear is a difficult
phenomenon to predict analytically, however
consideration should be given to the following:
-- operation in a contaminated environment;
-- sealing and design of the gear guard;
-- lubrication, see annex D.
5.3.4 Scuffing
Scuffing is severe adhesive wear on the flanks of
gear teeth. Adhesive wear is a welding and tearing
of themetal surface by the flank of themating gear. It
occurs when the lubricant film thickness is small
enough toallow the flanks of thegear teeth to contact
and slide against each other, see annex D.
Scuffing is not a fatigue phenomenon and it may
occur instantaneously. This phenomenon is a
function of lubricant viscosity and additives, operat-
ing bulk temperature of gear blanks, sliding velocity,
surface roughness of teeth, gear materials, heat
treatments, and surface pressure.
5.4 Bending strength
Bending strength of gear teeth is a fatigue phenome-
non related to the resistance to cracking at the tooth
root fillet in external gears. Typical cracks and
fractures are illustrated in ANSI/AGMA 1010--E95.
The bending strength ratings determined by this
standard are based on plate theory modified to
consider:
-- compressive stress at tooth roots caused by the
radial component of tooth loading;
-- non--uniform moment distribution resulting from
the inclined angle of the load lines on the teeth;
-- stress concentrations at the tooth root fillets;
-- load sharing between adjacent teeth in contact.
The intent of the AGMA strength rating formula is to
determine the load which can be transmitted for the
design life of the gearing without causing root fillet
cracking.
The basic theory employed in this analysis assumes
the gear tooth to be rigidly fixed at its base. If the rim
supporting the gear tooth is thin relative to the size of
the tooth and the gear pitch diameter, another critical
stressmay occur, not at the fillet, but in the root area.
In such cases, the rim thickness factor, KB, adjusts
the calculated bending stress number.
5.5 Conditions not covered by the bending
strength formula
The gear designer should ensure that the gear blank
construction is representative of the basic theory
embodied in this standard. Gear blank design is
beyond the scope of this standard, see annex C.
Occasionally, wear, surface fatigue, or plastic flow
may limit bending strength due to stress concentra-
tions around large, sharp cornered pits, or wear
steps on the tooth surface. However, these consid-
erations are outside the scope of this standard.
5.6 Non--uniform load
When the transmitted load is not uniform, consider-
ation shouldbegivennot only to thepeak loadand its
anticipated number of cycles, but also to intermedi-
ate loads and their numbers of cycles. This type of
load is often considered a duty cycle and may be
represented by a load spectrum. In such cases, the
cumulative fatigue effect of the duty cycle is consid-
ered in rating the gear set. A method of calculating
the effect of the loads under these conditions, such
as Miner’s Rule, is given in ISO 6336--6.
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
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6 Rating formulas
6.1 Pitting resistance
6.1.1 Pitting resistance power rating
The allowable transmitted pitting resistance power
rating is:
Pazm=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP ZN ZW
ZE
2
(1)
where
Pazm is allowable transmitted power for pitting
resistance per clause 1.0, at unity service
factor (CSF=1.0), kw;
ω1 is pinion speed, rpm;
b is net face width of narrowest member, mm;
ZI is geometry factor for pitting resistance, see
clause 7;
Kvm is dynamic factor, see clause 8;
KH is load distribution factor, see clause 12;
dw1 is operating pitch diameter of pinion, mm;
dw1=
2 a
u+ 1 (2)
a is operating center distance, mm;
u is gear ratio (never less than 1.0);
σHP is allowable contact stress number, N/mm2,
see clause 13;
ZN is stress cycle factor for pitting resistance,
see clause 15;
ZW is hardness ratio factor for pitting resistance,
see clause 11;
ZE is elastic coefficient, (N/mm2)0.5, see clause
9.
CAUTION: Ratings of both pinion and gear teeth must
be calculated to evaluate differences in material prop-
erties and number of tooth contact cycles under load.
Pitting resistance power rating is based on the lowest
value of the product σHP ZN ZW for each of the mating
gears.
6.2 Bending strength
6.2.1 Bending strength power rating
The allowable transmitted bending strength power
ratingis:
(3)Paym=
π ω1 dw1
6× 107 Kvm
b mt YJ σFP YN
KH KBm
where
Paym is allowable transmitted power for bending
strength per clause 1.0, at unity service fac-
tor (KSF = 1.0), kw;
mt is mn for spur gears;
(4)mt=
px tan β
π =
mn
cosβ
for helical gears
px is axial pitch, mm;
β is helix angle at the standard pitch diameter,
degrees. See ANSI/AGMA 1012--G05 for
additional information.
mn is normal metric module, mm;
YJ is geometry factor for bending strength, see
clause 7;
σFP is allowable bendingstress number,N/mm2,
see clause 13;
YN is stress cycle factor for bending strength,
see clause 15;
KBm is rim thickness factor, see 6.2.2.
CAUTION: Ratings of both pinion and gear teeth must
be calculated to evaluate differences in geometry fac-
tors, number of load cycles, and material properties.
Bending strength power rating is based on the lowest
value of the term
σFP YN YJ
KBm
for each of the mating
gears.
6.2.2 Rim thickness factor, KBm
Where the rim thickness is not sufficient to provide
full support for the tooth root, the location of bending
fatigue failure may be through the gear rim, rather
than at the root fillet. Published data [2] suggest the
use of a stress modifying factor in this case.
The rim thickness factor, KBm, is not sufficiently
conservative for components with hoop stresses,
notches, or keyways. This data is based on external
gears with smooth bores and no notches or key-
ways.
The rim thickness factor,KBm, adjusts the calculated
bending stress number for thin rimmed gears. It is a
function of the backup ratio, mB, see figure 1.
mB=
tR
ht
(5)
where
mB is back--up ratio;
tR is gear rim thickness below the tooth root,
mm;
ht is gear tooth whole depth, mm.
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0.8
1
1.2
1.4
1.6
1.8
2
0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50
R
im
th
ic
kn
es
s
fa
ct
or
,K
B
m
Backup ratio, mB
For mB< 1.0
KBm = --1.788 mB + 2.7636
Figure 1 – Rim thickness factor, KBm
The effects of webs and stiffeners can be an
improvement but are not accounted for in figure 1.
The effect of tapered rims has not been investigated.
Ratios less than 0.5 require special analysis and is
beyond the scope of this standard. When previous
experience or detailed analysis justifies, different
values of KBm may be used. The minimum value of
KBm is 1.0.
7 Geometry factors, ZI and YJ
7.1 Pitting resistance geometry factor, ZI
Geometry factor, ZI, evaluates the radii of curvature
of the contacting tooth profiles based on tooth
geometry. These radii are used to evaluate the
Hertzian contact stress in the tooth flank. Effects of
modified tooth proportions and load sharing are
considered.
7.2 Bending strength geometry factor, YJ
Geometry factor, YJ, evaluates the shape of the
tooth, position at which the most damaging load is
applied, and sharing of the load between oblique
lines of contact in helical gears. Both tangential
(bending) and radial (compressive) components of
the tooth load are included.
7.3 Calculation method
It is recommended that geometry factors, ZI and YJ,
bedeterminedbyAGMA908--B89. It includes tables
for some common tooth forms and the analytical
method for involute gears with generated root fillets.
For most designs covered by this standard, pointed
teeth are defined as normal chordal top land
thickness, san, less than 0.25 mn. Top lands smaller
than this value require additional review.
8 Dynamic factor, Kvm
CAUTION: Dynamic factor has been redefined as the
reciprocal of that used in previous AGMA standards. It
is now greater than 1.0. In earlier AGMA standards it
was less than 1.0.
8.1 Dynamic factor considerations
Dynamic factor, Kvm, accounts for internally gener-
atedgear tooth loadswhichare inducedbynon--con-
jugate meshing action of the gear teeth. Even if the
input torque and speed are constant, significant
vibration of the gear masses, and therefore dynamic
tooth forces, can exist. These forces result from the
relative accelerations between the gears as they
vibrate in response to an excitation known as
“transmission error”. Ideally, a gear setwould havea
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
11© AGMA 2006 ---- All rights reserved
uniform velocity ratio between the input and output
rotation. Transmission error is defined as the
departure fromuniform relative angularmotionof the
pair of meshing gears. It is influenced by all the
deviations from the ideal gear tooth form and ideal
spacing. The dynamic factor relates the total tooth
load including internal dynamic effects to the trans-
mitted tangential tooth load.
8.2 Approximate dynamic factor, Kvm
Figure 2 shows dynamic factors that shall be used.
The curves of figure 2 and the equations given are
based on empirical data, and do not account for
resonance.
CAUTION: Dynamic factor has been redefined to use
Av as defined in ANSI/AGMA 2015--1--A01. In previous
AGMA standards Kvm was based on Qv as defined in
AGMA 2000--A88. See annex J for a method to calcu-
late Kvm using Qv values.
Choices of curves Av = 7 through Av = 11 should be
based on transmission error. When transmission
error is not available, it is reasonable to refer to the
pitch accuracy, and to some extent profile accuracy,
as a representative value to determine the dynamic
factor. Av is related to the transmission accuracy
grade number.
8.2.1 Curves labeled Av = 7 through Av = 11
Theempirical curves of figure 2 are generated by the
following equations for integer values ofAv, such that
7≤ Av≤ 11.
The dynamic factor can be expressed as a function
of Av. Av can be approximated using the pitch
variation of the pinion and gear with the following
formula, rounded to the next higher integer. Values
of Av should be calculated for both gear and pinion,
and the higher value should be used for calculating
Kv.
For dT≤ 400 mm
(6)
Av=
ln fpt − ln 0.3 mn+ 0.003 dT+ 5.2
0.3466
+ 5
(rounded to the next highest integer)
1
1.1
1.2
1.3
1.4
1.5
1.6
0 2.5 5.0 7.5 10.0
Pitchline velocity, vt, m/s
D
yn
am
ic
fa
ct
or
,K
vm
Av = 7
Av = 10
Av = 9
Av = 8
Av = 11
Figure 2 -- Dynamic factor, Kvm
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
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For 400 mm < dT
(7)
Av=
ln fpt − ln 0.3mn+ 0.12 d0.5T + 4
0.3466
+ 5
(rounded to the next highest integer)
where
Av is transmission accuracy number per ANSI/
AGMA 2015--1--A01;
ln is natural log, loge;
fpt is single pitch deviation, mm;
mn is normal module, where
1.25≤ mn≤ 50;
dT is tolerance diameter, mm;
dT= de− 2mn (8)
de is outside diameter of pinion or gear, mm.
Av can also be estimated as the appropriate accura-
cy grade for theexpected pitch andprofile deviations
in accordance with ANSI/AGMA 2015--1--A01.
Kvm= Cmill+ 196.85 vtCmill 
Bmill
(9)
where
Cmill= 50+ 56 1− Bmill (10)
Bmill=
12−17− Av− (11−Av)210 
0.667
4
(11)
vt=
π ω1 dw1
60 000
(12)
where
Cmill is linear adjustment toKvm for open gearing;
Bmill is exponentialaccuracy adjustment to Kvm
for open gearing;
vt is pitchline velocity at operating pitch
diameter, m/s.
Valuesgreater thanAv=11arenot allowed. WhenAv
< 7, use Av = 7.
Theminimum value ofKvm when using this standard
is 1.02.
9 Elastic coefficient, ZE
The elastic coefficient, ZE, is defined by the following
equation:
ZE=
1
π1−ν21E1 +1−ν22E2  (13)
where
ZE is elastic coefficient, (N/mm2)0.5;
ν1, ν2 is Poisson’s ratio for pinion and gear,
respectively;
E1, E2 is modulus of elasticity for pinion and gear,
respectively, N/mm2.
For example, ZE equals 190 [N/mm2]0.5 for a steel
pinion and gear with ν = 0.3 and E = 2.05 × 105
N/mm2 for both elements.
When using an spheroidal graphitic (SG) iron gear
meshing with a steel pinion, ZE equals 184 [N/
mm2]0.5 for a steel pinionwith ν=0.3 andE = 2.05×
105N/mm2and for theSG iron gear, ν = 0.27 andE=
1.850× 105 N/mm2.
10 Service factor
The AGMA service factor as traditionally used in
these gear applications depends on experience
acquired in each specific application.
Service factor includes the combined effects of
overload, reliability, and other application related
factors. See annex I for additional information.
The allowable transmitted power for the gear set,Pa,
is determined:
Pa= the lesser of
Pazm
CSF
and
Paym
KSF
(14)
where
Pazm is allowable transmitted power for pitting re-
sistance at unity service factor, kw;
CSF is service factor for pitting resistance;
Paym is allowable transmitted power for bending
strength at unity service factor, kw;
KSF is service factor for bending strength.
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Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
13© AGMA 2006 ---- All rights reserved
11 Hardness ratio factor, ZW
The hardness ratio factor, ZW, depends upon:
-- gear ratio;
-- hardness of pinion and gear;
-- surface finish of surface hardened pinions.
When the pinion is substantially harder than the
gear, the work hardening effect increases the gear
capacity. Typical values of ZWare shown in figure 3.
These values are applied to the gear only. For the
pinion, ZW= 1.0.
Values of the hardness ratio factor, ZW, can be
calculated as follows:
ZW= 1.0+ A (u− 1.0) (15)
where
ZW is hardness ratio factor for pitting resistance;
u is gear ratio (never less than 1.0).
A is determined from the hardness ratio as:
For through hardened pinions meshing with through
hardened gears for the range:
1.2≤
HB1
HB2
≤ 1.7
and for surface hardened pinions with a surface
finish less than 3.2 Ra meshing with through
hardened gears for the range:
1.2≤
HB1
HB2
≤ 2.0
A= 0.00898 HB1
HB2
− 0.00829 (16)
where
HB1 is Brinell hardness of pinion, HB;
HB2 is Brinell hardness of gear, HB;
For
HB1
HB2
< 1.2, A = 0.00
For through hardened pinions meshing with through
hardened gears, and
HB1
HB2
> 1.7, A = 0.00698
1
1.02
1.04
1.06
1.08
1.10
1.12
1.14
1.16
1.18
1.20
1 5 10 15 20
H
ar
dn
es
s
ra
tio
fa
ct
or
,Z
W
Gear ratio
1.3
1.2
2.0
1.9
1.8
1.7
1.6
1.5
1.4
ZW = 1.0
HB1
HB2
Surface hardened
pinions only
Through hardened & surface
hardened pinions with less
than 3.2 Ra finish
Figure 3 -- Typical Hardness ratio factors, ZW
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
14 © AGMA 2006 ---- All rights reserved
For surface hardened pinions with a surface finish
less than 3.2 Ra, meshing with through hardened
gears, and
HB1
HB2
> 2.0, A = 0.00967
For surface hardened pinions with a surface finish
greater than or equal to 3.2 Ra, meshing with
through hardened gears
ZW= 1.0
HB1 may be determined for surface hardened
pinions measured with Rockwell C scale hardness
values between 45 Rc and 62 Rc by equation 17
+⎪
⎡
⎣
1.0
− 9.6806310−5 − 1.6255210−9H3
R1
 + 0.117524
HR1
⎪
⎤
⎦
(17)
HB1= 6.96608 10−2
where
HR1 is Rockwell C hardness of the pinion, HRC.
12 Load distribution factor, KH
The load distribution factor modifies the rating
equations to reflect the non--uniform distribution of
load along the lines of contact. The amount of
non--uniformity of the load distribution is caused by
many influences. See AGMA 927--A01 and ANSI/
AGMA 2101--D04 for additional information on this
topic.
12.1 Values for load distribution factor, KH
Load distribution factor is defined as: peak load
intensity divided by the average, or uniformly distrib-
uted, load intensity; i.e., ratio of peak to mean
loading.
KH= KHβ (18)
where
KH is load distribution factor;
KHβ is face load distribution factor.
12.2 Face load distribution factor, KHβ
The face load distribution factor accounts for the
non--uniform distribution of load across the gearing
face width. The magnitude of the face load
distribution factor is defined as peak load intensity
divided by average load intensity across the face
width.
This factor can be determined empirically or analyti-
cally. This standard provides an empirical method
only.
The empirical method requires a minimum amount
of information. This method is recommended for
relatively stiff gear designs which meet the following
requirements:
-- net facewidth to pinion pitch diameter ratio, b/dw1
≤ 2.0 (for double helical gears the gap is not in-
cluded in the face width);
-- face width up to 1270 mm;
-- contact across full face width of narrowest mem-
ber when loaded.
CAUTION: If b/dw1> 2.4 -- 0.029 (Ft (u+1)/(dw1 b u)) the
value of KH determined by the empirical method may
not be sufficiently conservative. In this case, it may be
necessary to modify the lead or profile of the gears to
arrive at a satisfactory result.
When gear elements are overhung, consideration
must be given to shaft deflections and bearing
clearances. Shafts and bearings must be stiff
enough to support the bending moments caused by
the gear forces to the extent that resultant deflec-
tions do not adversely affect gear contact. Bearing
clearances affect gear contact in the same way as
offset straddle mounted pinions. However, gear
elements with their overhang to the same support
side can compound the effect. This effect is
addressed by the pinion proportionmodifying factor,
KHpm. When the gap in a double helical gear set is
other than the gap required for tooth manufacture,
for example in a nested design, each helix should be
treated as a single helical set.
The following method will be used:
KHβ= 1.0+ KHmcKHpfKHpm+ KHma KHe
(19)
where
KHmcis lead correction factor;
KHpf is pinion proportion factor;
KHpmis pinion proportion modifier;
KHmais mesh alignment factor;
KHe is mesh alignment correction factor.
Lead correction factor, KHmc, modifies peak load
intensity when crowning or lead modification is
applied.
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
15© AGMA 2006 ---- All rights reserved
KHmcis 1.0 for gear with unmodified leads;
KHmcis 0.95 for gearing with leads properly modi-
fied by crowning or lead correction.
Pinion proportion factor, KHpf, accounts for deflec-
tions due to load. These deflections are normally
higher for wide face widths or higher b/dw1 ratios.
The pinion proportion factor can be obtained from
figure 4.For double helical gearing, pinion proportion factor
should be evaluated by considering b to be net face
width.
Values for KHpf as shown in figure 4 can be
determined by the following equations:
when 25 < b≤ 432
KHpf=
b
10 dw1
− 0.0375+ 0.0004926 b (20)
when 432 < b≤ 1250
− 0.000000353 b2 (21)
KHpf=
b
10 dw1
− 0.1109+ 0.000815 b
NOTE: For values of b
10 dw1
less than 0.05, use 0.05
for this value in equations 20 or 21.
Pinion proportion modifier, KHpm, is 1.0 due to
alignment correction at assembly.
Mesh alignment factor,KHma, accounts for misalign-
ment of the axes of rotation of the pitch cylinders of
the mating gear elements from all causes other than
elastic deformations. The value for mesh alignment
factor can be obtained from figure 5. When the
driven gear is mounted to equipment that is sup-
ported by rollers and tires, use the roller supported
curve. When the driven gear is mounted to
equipment that is supported by bearings, use the
bearing supported curve.
For double helical gearing, mesh alignment factor
should be evaluated by considering b to be one half
of the net face width.
Values for the two curves of figure 5 are defined as
follows:
KHma= A+ B(b)+ C(b)
2 (22)
See table 2 for values of A, B and C.
Mesh alignment correction factor is used to modify
the mesh alignment factor when assembly tech-
niques improve the effective mesh alignment. The
following value is suggested for the mesh alignment
correction factor:
KHe is 0.80 because the gearing is adjusted at
assembly.
875
Face width, b, mm
See equations 20 and 21
For determining KHpf
For b/dw1 < 0.5 use
curve for b/dw1 = 0.5
P
in
io
n
pr
op
or
tio
n
fa
ct
or
,K
H
pf
0 125 250 375 500 625 750 1000 1125 1250
b/dw1
ratio
2.00
1.50
1.00
0.50
0
0.10
0.20
0.30
0.40
0.50
0.60
Figure 4 -- Pinion proportion factor, KHpf
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
16 © AGMA 2006 ---- All rights reserved
For determination of KHma, see equation 22
Face width, b, mm
0.20
0.10
0.30
0.40
0.50
0.60
0.70
0.80
0.0
0.90
0 125 250 375 500 625 750 875
Roller supported
Bearing supported
M
es
h
al
ig
nm
en
tf
ac
to
r,
K
H
m
a
1000 1125 1250
Figure 5 -- Mesh alignment factor, KHma
Table 2 -- Empirical constants: A, B, and C
Curve A B C
Roller supported 2.47 x 10--1 0.657 x 10--3 --1.186 x 10--7
Bearing supported 1.27 x 10--1 0.622 x 10--3 --1.69 x 10--7
13 Allowable stress numbers, σHP and σFP
Allowable stress numbers for gear materials vary
with items such as material composition, cleanli-
ness, residual stress, microstructure, quality, heat
treatment, and processing practices.
Allowable stress numbers in this standard (tables 3
and 4) are determined or estimated from laboratory
tests and accumulated field experiences. They are
based on 10 million stress cycles, unidirectional
loading and 99 percent reliability. Allowable stress
numbers are designated as σHP and σFP, for pitting
resistance and bending strength respectively. For
service life other than 10 million cycles, allowable
stress numbers are adjusted by the use of stress
cycle factors, see clause 15.
Table 3 -- Allowable contact stress number, σHP, for steel and spheroidal graphitic iron gears
Material
designation
Heat
treatment
Minimum
surface
Allowable contact stress number2),
σHP, N/mm2designation treatment surfacehardness Grade M1 Grade M2
Steel3) Through hardened1), 4) see figure 6 See figure 6 See figure 6
Induction hardened5) see table 8 1170 1345
Carburized & hardened5) 55 HRC 1240 1450
Spheroidal
graphitic iron
Spheroidal graphitic iron
through hardened1)
See figure 8
NOTES:
1) Hardness to be equivalent to that at the start of active profile in the center of the face width.
2) See tables 5, 7, and 8 for major metallurgical factors for each stress grade of steel gears and table 6 for spheroidal
graphitic iron.
3) Steel selected must be compatible with the heat treatment process selected and hardness required.
4) These materials must be annealed or normalized as a minimum.
5) Allowable stress numbers indicated may be used with the minimum case depths prescribed in 13.1.
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
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Table 4 -- Allowable bending stress number, σFP, for steel and spheroidal graphitic iron gears
Material
designation
Heat
treatment
Minimum surface
hardness
Allowable bending stress number2),
σFP, N/mm2
Grade M1 Grade M2
Steel3) Through hardened1) See figure 7 See figure 7 See figure 7
Induction hardened4)
with type A pattern5)
See table 8 310 380
Carburized & hardened4) 55 HRC 380 425
Spheroidal
graphitic iron
Spheroidal graphitic iron
through hardened1)
See figure 9
NOTES:
1) Hardness to be equivalent to that at the root diameter in the center of the tooth space and face width.
2) See tables 5, 7, and 8 for major metallurgical factors for each stress grade of steel gears and table 6 for spheroidal
graphitic iron.
3) Steel selected must be compatible with the heat treatment process selected and hardness required.
4) Allowable stress numbers indicated may be used with the minimum case depths prescribed in 13.1.
5) See figure 10 for type A flank and root hardness patterns.
The effective case depth for induction hardened
pinions is defined as the depth below the surface at
which the hardness is equivalent to 10 Rockwell ‘C’
points below the specified minimum surface
hardness.
Allowable stress numbers for gears are established
by specific quality control requirements for each
material type and grade. All requirements for the
quality grade must be met in order to use the stress
values for that grade. This can be accomplished by
specifically certifying each requirement when speci-
fied. It is not the intent of this standard that all
requirements for quality grades be certified, but that
practices and procedures be established for their
compliance on a production basis. Intermediate
values shall not be used since the effect of
deviations from the quality standards cannot be
evaluated easily. When justified by testing or
experience, higher stress levels for any given grade
may be used. Allowable stress numbers are shown
in tables 3 and 4, and figures 6 through 9.
13.1 Guide for case depth of surface hardened
pinions
Surface hardened pinion teeth require adequate
case depth to resist the subsurface shear stresses
developed by tooth contact loads and the tooth root
fillet tensile stresses, but depthsmust not be sogreat
as to result in brittle tooth tips and high residual
tensile stress in the core.
The effective case depth for carburized and hard-
ened pinions is defined as the depth below the
surface at which the Rockwell ‘C’ hardness, HRC,
has dropped to 50 HRC or equivalent.
A minimum effective case depth, he min, at the pitch
line for carburized and induction hardened pinion
teeth as a function of pitch is shown in figure 11.
Care should be exercised when choosing case
depth, such that adequate case depths prevail at the
tooth and root fillet, and that tooth tips are not over
hardened and brittle. The actual case depth toler-
ance is determined by the manufacturer or by
contractual agreement. It is recommended that the
case depth does not exceed he max.
he max= the lesser of 0.4 mn or 0.56 san (23)
where
he max is suggested maximum effective case
depth at the pitch line, mm;
san is normal tooth thicknessat the top land of
the pinion in question, mm.
If he min from figure 11 (with case depth tolerance
considered) exceeds he max, a careful review of the
proposed design is required. Changing the profile
shift, lowering the operating pressure angle, or using
a coarser pitch will increase he max.
For induction hardened teeth using a single tooth
hardening method, it is critical that the hardened
areas from each tooth flank do not cross at the tip of
the tooth. This prevents tempering back of a
previously hardened tooth surface.
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
18 © AGMA 2006 ---- All rights reserved
150 200 250 300 350 400 450
690
862
1034
1207
Brinell hardness, HB
517
Metallurgical and quality control procedures required
Grade M1
σHP = 2.061 HB + 270
Grade M2
σHP = 2.407 HB + 236
A
llo
w
ab
le
co
nt
ac
ts
tr
es
s
nu
m
be
r,
σ H
P
100
N
/m
m
2
Figure 6 -- Allowable contact stress number for through hardened steel gears, σHP
69
138
207
276
345
150 200 250 300 350 400 450
Grade M2
σFP = 0.703 HB + 113
Grade M1
σFP = 0.49 HB + 115
Metallurgical and quality
control procedures required
A
llo
w
ab
le
be
nd
in
g
st
re
ss
nu
m
be
r,
σ F
P
100
Brinell hardness, HB
N
/m
m
2
Figure 7 -- Allowable bending stress number for through hardened steel gears, σFP
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
19© AGMA 2006 ---- All rights reserved
150 200 250 300 350
690
862
1034
1207
Brinell hardness, HB
517
Metallurgical and quality control procedures required
Grade M1
σHP = 2.086 HB + 188.4
Grade M2
σHP = 2.26 HB + 222.1
A
llo
w
ab
le
co
nt
ac
ts
tr
es
s
nu
m
be
r,
σ H
P
100
N
/m
m
2
Figure 8 -- Allowable contact stress number for spheroidal graphitic iron gears, σHP
69
138
207
276
345
150 200 250 300 350
Grade M2
σFP = 0.542 HB + 87.1
Grade M1
σFP = 0.507 HB + 81.4
Metallurgical and quality control procedures required
A
llo
w
ab
le
be
nd
in
g
st
re
ss
nu
m
be
r,
σ F
P
100
Brinell hardness, HB
N
/m
m
2
Figure 9 -- Allowable bending stress number for spheroidal graphitic iron gears, σFP
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
20 © AGMA 2006 ---- All rights reserved
Table 5 -- Metallurgical characteristics for steel pinions and gears
Item Characteristic1) Grade M1 Grade M2
1 Material chemistry Certification not required. Test report only per ASTM A751. Medium carbon alloy steel.
0.025% maximum sulfur.
2 Grain size Certification not required. Predominantly 5 or finer. Test report only per ASTME112 or ISO
643.
3 Hardenability Certification not required. A minimum hardenability, which is appropriate for part size and
cooling rate, should be specified per ASTM A255 or ISO 642, or
by hardenability calculation per ASTM A255.
4 Non--metallic inclusions (clean-
liness, steelmaking)2)
Certification not required. Wrought gearing: Capable of meeting (certification not required)
SAE/AMS 2301, ASTM A866 or SAE J422 S2--O2.
Cast gears: Only permissible if primarily round (Type 1) sulfide
inclusions.
5.1 Material form3) Forgings per either ASTM A290 or ASTM A291.
Bar stock per ASTM A29, ASTM A304 or ISO 683--1.
Castings per ASTM A148.
5.2 Material reduction ratio
(wrought only)
At least 3 to 1 for ingot cast.
Continuous cast not applicable.
6 In process welding5), 13) Welding in zone 14) is acceptable only if done using heat treatable welding rod, is followed by
a full heat treatment as defined in item7Grade M2, andahardness traverse is performed. No
heat affected zone is allowed and the hardness of the weld must meet the requirements of
item 8.
It is recommended that welds outside of zone1use compatible heat treatablewelding rodand
be followed by a full heat treatment as defined in item 7 below.
Welds outside of zone 1 using non--heat treatable welding rod and without a full heat treat-
ment, are acceptable only after an engineering evaluation.
In addition, for fabricated gearing all welding shall be in accordance with the requirements of
AWS D1.1. Complete welding procedure specifications (WPS) in accordance with Section 4
of AWS D1.1 and a weld map correlating all welds with the applicable WPS are required.
WPSshall include procedure qualification records (PQR) unless aWPS is exempt fromquali-
fication perSection3of AWSD1.1. All welding shall be performedbywelders orweldingoper-
ators qualified in accordance with ASME Boiler and Pressure Vessel Code Section IX or
ASTM A488.
7 Heat treatment Certification not required. Normalize and temper, 538°C min. temper or quench and
temper, 482°C min. temper. Certified heat treatment record is
required. All fabricated gear weldments are to be thermally
stress relieved in accordance with AWS D1.1 guidelines, fol-
lowed by a slow cool prior to machining.
8 Hardness testing4), 6) Certification not required. Hardness testing is required on semi--finished blanks with 3 mm
maximum stock. The minimum measured hardness value shall
meet the specified design requirement. Amaximum40HB range
in measured hardness values is recommended.
For pinions, using only Brinell hardness testers, hardness mea-
surements shall be on the outside diameter in four places located
approximately 90 degrees apart around the circumference of the
pinion.
For gears, using only Brinell or Equotip hardness testers, a mini-
mum of twelve measurements shall be taken, four equally
spaced on each rim edge at the tooth root diameter. If individual
risers are used for casting, the hardness measurements shall
also be taken around the circumference on the outside diameter
at mid--face. If in--process welding has been performed in zone
1, then traverse hardness testing is also required across each
weld.
(continued)
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
21© AGMA 2006 ---- All rights reserved
Table 5 (continued)
Item Characteristic1) Grade M1 Grade M2
9 Mechanical testing3) Certification not required. If required and defined by contractual agreement, mechanical
properties7) are to be obtained in accordance with ASTM E8 for
both pinions and gears.
10 Microstructure2) Certification not required. Sound metallurgical practice dictates that the microstructure re-
quirements are maintained in the tooth area. The microstructure
should be free of blocky ferrite and be within the following limits:
Controlling section size, Upper transformation
mm products, maximum
at least less than
---- 127 10%
127 ---- Hardness must be
obtainable at roots with
minimum specified temper
11 Ultrasonic inspection4), 5), 8), 9)
Wrought material
(Rims for fabricated gears;
through hardened pinions)
Certification not required. 100% ultrasonic inspection in two (2) perpendicular directions,
per ASTM A388 is required, and the following limits apply:
-- No indicationslarger than 50% of the reference back
reflection.
-- No continuous indications over an area larger than twice the
diameter of the search unit, regardless of amplitude.
-- No reflections that produce indications accompanied by a
50% loss of back reflection, not attributable to the geometric
configuration.
For pinions, above UT applies in radial direction, 360 degrees
around, and axially from both ends.
All test surfaces to be machined to a maximum of 6.2 mm surface
finish.
Castings
Flat bottom hole (FBH)
technique
Certification not required. Ultrasonic inspection per ASTMA609 in two perpendicular direc-
tions to the following limits. All test surfaces to be machined to a
minimum of 6.2 mm surface finish:
-- Zone 14) -- Level 1 -- 3 mm flat bottom hole straight beam
-- Zone 24) -- Level 2 -- 6 mm flat bottom hole straight beam
-- For both zones, paragraphs 10.2.1, 10.2.2 and 10.2.3 of
ASTM A609 shall apply. Also cracks, tears, cold shuts, un-
fused chaplets, or a complete loss of back reflection not attrib-
utable to the geometric configuration (a drop to less than 5%
of full screen height) are not acceptable.
Bi--metallic rim Certification not required. Fusion bond is to be examined in accordance with ASTM A578
but using a 75 mm grid pattern and acceptance is per Level B of
ASTM A578.
Fabricated gear body Certification not required. All full penetration welds are to be examined in accordance with
section 6 of AWS D1.1, using all three standard transducers.
12 Surface microstructure consid-
ering subsequent stock
removal.
Should meet the following surface related characteristic:
Decarburization. Any of the
following methods are
acceptable.
-- Method 1. File testing.
-- Method 2. Reduction of sur-
face hardness by two load
method.6)
-- Method 3. Metallographic
evaluation.
Not applicable.
Certification not required.
Certification not required.
Not applicable.
Maximum 2 HRC points or equivalent by conversion.
No total or partial decarburization apparent on the finished tooth.
(continued)
Copyright American Gear Manufacturers Association 
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Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
22 © AGMA 2006 ---- All rights reserved
Table 5 (concluded)
Item Characteristic1) Grade M1 Grade M2
13 Magnetic particle inspection of
gear blank (zone 2)4), 5), 7), 8), 9),
10), 11), 13)
Certification not required. 100%magnetic particle inspection required per ASTME1444 for
wrought or cast gear blanks. Any indication greater than 6 mm
shall be reported. No cracks, seams, laps or tears are allowed.
-- Fabricated Certification not required. 100%magnetic particle inspection is required for plate edges per
section 6 of AWSD1.1 just prior towelding, and acceptance is per
paragraph 5.15 of AWS D1.1. 100%magnetic particle examina-
tion of weld backgouging is required to be performed per section
6 of AWS D1.1, and acceptance is per paragraph 6.10 and table
6.1 of AWS D1.1.
-- Cast Certification not required. 100% wet magnetic particle inspection is required per ASTM
E1444 for cast gear blanks. Any indication greater than 6 mm
shall be reported.
14 Magnetic particle inspection of
finished teeth and roots (zone
1). 4), 9)
Certification not required. Inspection to the following limits:
-- Magnetic particle technique per ASTM E1444 should use the
true continuousmethod, wet fluorescent or wet visible, with di-
rect or indirect magnetization, in two directions.
For gears, acceptance criteria per tooth flank
-- Sum of the lengths must not exceed 10% of face width.
-- Any indication greater than 5 mm shall be reported.
-- Any single linear indication located below the operating pitch
diameter, andwhich lies parallel to the teeth, shall be reported.
-- No cracks, seams, laps or tears are allowed.
For pinions acceptance criteria per tooth flank are no linear indi-
cations, cracks, seams, laps or tears.
15 100% visual inspection of the
finished gearing10), 11)
Inspection to the following limits: No linear indications, cracks, seams, laps or tears.
16 Shot peening12) Shot peening per SAE/AMS--S--13165 may be used to increase surface residual compres-
sive stress.
NOTES:
1) Metallurgical requirements assume homogeneous composition. In practice, microsegregation and/or banding occurs in steels.
This microsegregation can produce variations in microstructure and properties that need to be assessed.
2) Grade requirements for non--metallic inclusions, andmicrostructure characteristics apply only to thoseportions of the gearingmate-
rial where the teeth will be located in zone 1, see note 4.
3) See annex H for mechanical properties.
4) Zone 1 is defined as the volume within the gear blank outside diameter extending to a minimum depth of 25 mm below the roots of
the finished gear teeth including the segment joint flanges from the outside diameter to 25mmbelow the roots of the finished gear teeth.
Zone 2 is defined as the gear rim and segment joint flange volumes not included in Zone 1 and any other parts of the gear structure that
the purchaser and seller consider necessary to examine.
5) All references to AWS D1.1 mean the requirements of AWS D1.1 structural welding code as applicable to cyclically loaded non--
tubular connections.
6) See ASTM A370, ASTM E140 or ISO 6336--5, annex C for hardness conversion tables.
7) Mechanical properties are defined to mean tensile, yield, elongation and reduction of area.
8) In--process ultrasonic and/ormagnetic particle inspection of gearing blanks is recommended for large diameter parts to detect flaws
before incurring the expense of further machining.
9) Linear is defined as any indication with length greater than 3 times its width.
10) Removal of defects that exceed the stated limits is acceptable, provided integrity of the gear is not compromised.
11) Defects in non--functional areas require engineering disposition.
12) It is recommended that ANSI/AGMA 2004--B89 be reviewed to determine if the benefits of surface residual compressive stress
achieved by shot peeningmay be beneficial to the particular application. Shot peening of the flanks of gear teeth should be reviewed to
ensure that no detrimental effects are caused to the gear set.
13) Not applicable for pinions.
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
23© AGMA 2006 ---- All rights reserved
Table 6 -- Metallurgical characteristics for spheroidal graphitic iron gears
Item Characteristic1) Grade M1 Grade M2
1 Material chemistry Certification not required. Test report only per ASTM E351.
2 Microstructure Certification not required. Test per ISO 945 or ASTM A247. Graphite form predominately
VI, some V acceptable. No coarser than nodule size 5.
3 Material form ASTM A536 and ISO 1083 or by contractual agreement.
4 Heat treatment Not specified. Not specified.
5 Hardness testing2) Certification not required. Hardness testing is required on semi--finished gear blanks, 3mm
maximum stock and using only Brinell or Equotip hardness test-
ers. Theminimummeasured hardness value shall meet the spe-
cified design requirement. Amaximum40HB range inmeasured
hardness values is recommended. A minimum of twelve mea-
surements shall be taken, four equally spaced on each rim edge
at the tooth root diameter. If individual risers are used for casting,
the hardnessmeasurements on the cope side shall be performed
in the riser area. Four equally spaced measurements shall also
be taken aroundthe circumference on the outside diameter at
mid--face.
6 Mechanical testing3) Certification not required. Mechanical properties are to be obtained in accordance with
ASTME8. Properties for each gear segment are to be confirmed
by testing of specimens representative of the rim thickness. Test
specimens shall undergo the same heat treatment with the gear
segment they represent.
7 Stress relief Certification not required. Either in--mold or furnace stress relief required. In--mold stress
relieving shall be monitored with thermocouples until the casting
has cooled to 204°C.
8 Weld repair Not allowed in the rim. Not allowed.
9 Ultrasonic inspection4), 5), 6)
Flat bottom hole (FBH) tech-
nique
Certification not required. Ultrasonic inspection per ASTMA609 in two perpendicular direc-
tions to the following limits. All test surfaces to be machined to a
maximum of 6.2 mm surface finish.
-- Zone 14) – Level 1-- 3 mm flat bottom hole straight beam
-- Zone 24) – Level 2 -- 6 mm flat bottom hole straight beam
For both zones paragraphs 10.2.1, 10.2.2 and 10.2.3 of ASTM
A609 shall apply. Also, cracks, tears, cold shuts, unfused chap-
lets or a complete loss of back reflection not attributable to the
geometric configuration (a drop to less than 5% of full screen
height) are not acceptable.
Calibration reference blocks shall be nodular cast iron and the
DGS technique is also acceptable.
10 Nodularity (sound velocity) Minimum sound velocity of 5486 m/s at four equally spaced points on the rim of each gear
segment is required.
11 Magnetic particle inspection of
gear blank (zone 2) 4), 5), 6), 7), 8)
Certification not required. 100%magnetic particle inspection required per ASTME1444 for
cast gear blanks. Any indication greater than 6 mm shall be re-
ported. No cracks, seams, laps or tears are allowed
12 Magnetic particle inspection of
finished gear teeth and roots
(zone 1) 4), 5), 6), 9)
Inspection to the following limits:
The magnetic particle technique per ASTM E1444 should use the true continuous method,
wet fluorescent or wet visible, with direct or indirect magnetization, in two directions.
Acceptance criteria per tooth flank:
-- Sum of the lengths must not exceed 10% of face width.
-- Any indication greater than 6 mm shall be reported.
-- Any single linear indication located below the operating pitch diameter which lies parallel
to the teeth shall be reported.
-- No cracks, seams, laps or tears are allowed.
13 100% visual inspection of the
finished gearing 7), 8), 9)
Inspection to the following limits: No linear indications, cracks, seams, laps or tears are
allowed.
(continued)
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
24 © AGMA 2006 ---- All rights reserved
Table 6 (concluded)
Item Characteristic1) Grade M1 Grade M2
14 Shot peening 10) Shot peening per SAE/AMS--S--13165 may be used to increase surface residual compres-
sive stress.
NOTES:
1) Metallurgical requirements assume homogeneous composition. In practice, microsegregation occurs in nodular cast irons. This
microsegregation can produce variations in microstructure and properties that need to be assessed.
2) See ASTM A370, ASTM E140 or ISO 6336--5, annex C for hardness conversion tables.
3) Mechanical properties are defined to mean tensile, yield, elongation and reduction of area.
4) Zone1 is definedas the volumewithin thegear blank outsidediameter extending toaminimumdepth of 25mmbelow the roots of the
finished gear teeth including the segment joint flanges from the outside diameter to 25 mm below the roots of the finished gear teeth.
Zone 2 is defined as the gear rim and segment joint flange volumes not included in Zone 1 and any other parts of the gear structure that
the purchaser and seller consider necessary to examine.
5) Dross is not acceptable unless there is an engineering evaluation performed.
6) In--process ultrasonic and/ormagnetic particle inspection of gearing blanks is recommended for large diameter parts to detect flaws
before incurring the expense of further machining.
7) Removal of defects that exceed the stated limits is acceptable, provided integrity of the gear is not compromised.
8) Defects in non--functional areas require engineering disposition.
9) Linear is defined as any indication with length greater than 3 times its width.
10) It is recommended that ANSI/AGMA 2004--B89 be reviewed to determine if the benefits of surface residual compressive stress
achieved by shot peeningmay be beneficial to the particular application. Shot peening of the flanks of gear teeth should be reviewed to
ensure that no detrimental effects are caused to the gear set.
Table 7 -- Metallurgical characteristics for wrought carburized and hardened pinions
Item Characteristic1) Grade M1 Grade M2
1 Material chemistry Test report only per
ASTM A751. Alloy steel
0.025% maximum sulfur.
Test report only per ASTM A751. Alloy steel. 0.025% maximum
sulfur, 2.0 ppm maximum hydrogen per ASTM E1019.
2 Grain size Predominantly 5 or finer.
Verification not required.
Predominantly 5 or finer. Test report only.
3 Hardenability Not specified. A minimum hardenability which is appropriate for part size and
quench severity should be specified.
4 Non--metallic inclusions (clean-
liness, steelmaking)2)
Not specified. Alternative A
-- Capable of meeting bearing quality per ASTM A534.
Alternative B all of the following:
-- The steel must be certified:
-- electric furnace practice
-- ladle refined
-- deoxidized
-- vacuum degassed
-- bottom poured ingot
-- protected from reoxidation during teeming or casting
-- capable of oxygen content of 20 ppm maximum
-- capable of cleanliness confirmation by either ASTM E45
or ISO 4967 Method B Plate II with 194 mm2 inspection
area. Acceptable if does not exceed:
Type Fine Thick
A (sulfide) 3.0 3.0
B (alumina) 2.5 1.5
C (silicate) 2.5 1.5
D (globular oxide) 2.0 1.5
Alternative C:
Capable of meeting SAE/AMS 2301 or SAE J422 S2--02
5.1 Material form Forgings per eitherASTMA290orASTMA291. Bar stock perASTMA29,ASTMA304or ISO
683--11.
5.2 Material reduction ratio At least 3 to 1 for ingot cast. Continuous cast is not allowed.
(continued)
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
25© AGMA 2006 ---- All rights reserved
Table 7 (continued)
Item Characteristic1) Grade M1 Grade M2
6 Ultrasonic inspection3) 100% ultrasonic inspection in two (2) perpendicular directions, per ASTM A388 is required,
and the following limits apply:
-- No indications larger than 50% of the reference back reflection.
-- No continuous indications over an area larger than twice the diameter of the search unit,
regardless of amplitude.
-- No reflections that produce indications accompanied by a 50% loss of back reflection, not
attributable to the geometric configuration.
Above UT applies in radial direction, 360 degrees around, and axially from both ends.
All test surfaces to be machined to a maximum of 6.2 mm surface finish.
UT is to be redone after carburization, in areas where possible, and compared with forging
blank UT. Any changes not associated with method accuracy shall be evaluated as to
acceptability.
7 Tempering after case
hardening
Required. Required.
8 Surface hardness in tooth area.
Method of inspection is
case hardness of a test coupon
Should meet the following characteristics when using only Rockwell mobile or Equotip hard-
ness testers:
case hardness of a test coupon4), 5), 6) 55 minimum HRC or equivalent.
9 Case depth considering subse-
quent stock removal
Should meet the characteristics of 9.1 and 9.2.
9.1 Effective case depth in finished
condition 6), 7)
Minimum effective case depth per figure 11.
9.2 Effective case depth minimum
at root radius 6), 7)
Not specified. Verification not required. Capable of meeting 50% of minimum
specified effective case at one--half tooth height recommended.
10 Core hardness after case hard-
ening of test coupon 7)
Verification not required.
Capable of meeting 21
HRC minimum.
Verification not required. Capable of meeting 25 HRCminimum.
11 Surface carbon (typical)8)
For up to 2.5% total nominal
alloy content
2.5% to 3.5% total nominal alloy
content
Over 3.5% total nominal alloy
content
0.60 -- 1.10%C
0.60 -- 1.10%C
0.60 -- 1.10%C
0.60 -- 1.10%C
0.60 -- 1.00%C
0.65 -- 0.95%C
12 Surface microstructure consid-
ering subsequent stock remov-
al 7), 9)
The first 50 -- 75 mmof casemicrostructure should meet the surface hardness requirement of
the specific grade and also meet the following surface related characteristics and the
requirements of Item 13:
12.1 Intergranular oxidation (IGO)
(see figure 9, AGMA 923--A00)
Minimum specified effective
case depth, mm
at less
least than
1.5 2.3
2.3 3.0
3.0 ----
Not specified.
Maximum allowable depth, mm
38
50
63
(continued)
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
26 © AGMA 2006 ---- All rights reserved
Table 7 (continued)
Item Characteristic1) Grade M1 Grade M2
12.2 Non--martensitic transforma-
tion products (see figure 11,
AGMA 923--A00)10)
Minimum specified effective
case depth, mm
at less
least than
1.5 2.3
2.3 3.0
3.0 ----
Not specified.
Maximum allowable depth, mm
38
50
63
12.3 Decarburization. Any of the
following methods are accept-
able:
-- Method 1. Reduction of sur-
face hardness by two load
method or reduction of case
hardness.6)
-- Method 2. Metallographic
evaluation.
Minimum specified effective
case depth, mm
at less
least than
1.5 2.3
2.3 3.0
3.0 ----
Not specified.
Maximum3HRCpoints or equivalent belowmaximummeasured
hardness by conversion but measuring at least 55 HRC or equiv-
alent by conversion in the finished state.
No ferrite (total decarburization) is permissible in the casemicro-
structure of the pinion tooth. No partial decarburization apparent
on active tooth profile.
Maximum allowable depth in root, mm
38
50
63
13 Case microstructure consider-
ing subsequent stock removal
disregarding corner effects 7)
Microstructure of the first 20% of the minimum specified effective case depth should be pre-
dominantly tempered martensite. Additional requirements for the case microstructure are
given in item 14.
14.1 Carbide precipitation in the
case
Continuous carbide net-
work per AGMA 923--A00
figure 1 is not acceptable,
but semi--continuous car-
bide network per AGMA
923--A00, figure 2 is ac-
ceptable.
Semi--continuous carbide network per AGMA 923--A00, figure 2
is not acceptable, but discontinuous carbides per AGMA
923--A00, figure 3 are acceptable. Maximum acceptable length
of any carbide is 20 mm.
14.2 Retained austenite in the
case5)
Not specified. Retained austenite 25%maximumdeterminedmetallographical-
ly by comparison with AGMA 923--A00 figure 13. Rejection of
piece parts shall only be based on case hardness. The minimum
microhardness at 100 mm or through the area of highest retained
austenite shall be 55 HRC. 6), 9)
14.3 Microstructure of the case to a
depth of 0.25 mm or the first
20% of the minimum specified
effective case depth, whichever
is smaller, along the flank (for
pitting resistance rating)
Not specified.
Untempered martensite
is acceptable.
Primarily tempered martensite with 5% maximum non--marten-
sitic structures, carbide precipitation per item 14.1, retained aus-
tenite per item14.2, and other surfacemicrostructures as defined
under items 12.1 through 12.3.
14.4 Microstructure of the case to a
depth of 0.25 mm or the first
20% of the minimum specified
effective case depth, whichever
is smaller, at the root fillet (for
bending strength rating)
Not specified.
Untempered martensite
is acceptable.
Primarily tempered martensite with 10%maximum non--marten-
sitic structures, carbide precipitation per item 14.1, retained aus-
tenite per item14.2, and other surfacemicrostructures as defined
under items 12.1 through 12.3.
(continued)
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
27© AGMA 2006 ---- All rights reserved
Table 7 (concluded)
Item Characteristic1) Grade M1 Grade M2
15 Core microstructure 7), 11) Not specified. Sound metallurgical practice dictates that the core microstruc-
ture requirements are maintained in the tooth area to a depth of
twice the minimum specified effective case depth or 2.5 mm,
whichever is less, below the minimum specified effective case
depth. Microstructure in this zone should be predominantly tem-
pered martensite. This microstructure zone should be free of
blocky ferrite, pearlite, and measurable bainite. Below this zone
the coremicrostructure should be free of blocky ferrite and be pri-
marily temperedmartensite with some acicular ferrite and bainite
permissible.
16 Surface temper etch inspection
of ground teeth
Not specified. Verification not required. Capable of meeting FB2 as defined in
ANSI/AGMA 2007--C00 is recommended.
17 100%magnetic particle inspec-
tion of finished teeth, roots and
other machined surfaces 3), 12)
Inspection to the following limits:
The magnetic particle technique per ASTM E1444 should use the true continuous method,
wet fluorescent or wet visible, with direct or indirect magnetization, in two directions.
No indications are permitted.
18 100% visual inspection of the
finished pinion
Inspection to the following limits:
No linear indications, cracks, seams, laps or tears allowed.
19 Shot peening 13) Shot peening per SAE/AMS--S--13165 may be used to increase surface residual compres-
sive stress.
NOTES:
1) Metallurgical requirements assume homogeneous composition. In practice microsegregation and banding occurs in steels. This
microsegregation can produce variations in microstructure and properties that need to be assessed.
2) Intentional additions of calcium or calcium alloys for deoxidation or inclusion and shape control are not permitted unless specifically
approved by the purchaser. The use of lime or fluorspar, or both, in the steelmaking slag is acceptable.
3) In--process ultrasonic and/ormagnetic particle inspection of gearing blanks is recommended for large diameter parts to detect flaws
before incurring the expense of further machining.
4) Root hardness may be less than flank hardness, depending on the size of the gear and the quench process.
5) If cold treatment is performed, it is recommended that it be preceded by tempering at 150°Cminimum in order tominimize formation
ofmicrocracks. Retempering is required after cold treatment. Cold treatment should not be used to transform largeamounts of retained
austenite (e.g., 50%) to gain excessive improvements in hardness, even with prior tempering.
6) See ASTM A370, ASTM E140 or ISO 6336--5, annex C for hardness conversion tables.
7) See AGMA 923--A00, clauses 3 and 4 for discussion of test coupons.
8) Optimum pitting resistance is best achieved at surface carbon levels above the eutectoid carbon for a given alloy chemistry.
9) If excessive,salvage may be possible by processes such as shot peening per item 19 or by grinding, provided the integrity of the
gearing is not compromised.
10) At maximum allowable depths the surface may not be file hard and may not have the expected residual stress profile.
11) Grade requirements for non--metallic inclusions andmicrostructure characteristics apply only to those portions of the gear material
where the teeth will be located to a depth below the finished tooth tip of at least 1.5 times the tooth height.
12) Indications less than 0.4 mm are not considered.
13) It is recommended that ANSI/AGMA 2004--B89 be reviewed to determine if the benefits of surface residual compressive stress
achieved by shot peeningmay be beneficial to the particular application. Shot peening of the flanks of gear teeth should be reviewed to
ensure that no detrimental effects are caused to the gearset.
Table 8 -- Metallurgical characteristics for wrought induction hardened pinions
Item Characteristic1)
Type A (flank and root hardening) only
Item Characteristic1)
Grade M1 Grade M2
1 Material chemistry Test report only per ASTM A751. Alloy steel. 0.025% maximum sulfur.
2 Grain size Predominantly 5 or finer.
Verification not required.
Predominantly 5 or finer. Test report only.
3 Hardenability Not specified. A minimum hardenability which is appropriate for part size and
quench severity should be specified.
4 Non--metallic inclusions (clean-
liness, steelmaking) 2)
Not specified. Wrought gearing. Capable of meeting (certification not required)
SAE/AMS 2301, ASTM A866 or SAE J422 S2--O2.
(continued)
Copyright American Gear Manufacturers Association 
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Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
28 © AGMA 2006 ---- All rights reserved
Table 8 (continued)
Item Characteristic1)
Type A (flank and root hardening) only
Item Characteristic1)
Grade M1 Grade M2
5.1 Material form Forgings per either ASTM A290 or ASTM A291.
Bar stock per ASTM A29, ASTM A304 or ISO 683--1.
5.2 Material reduction ratio
(wrought only)
At least 3 to 1 for ingot cast.
Continuous cast not applicable.
6 Heat treatment prior to surface
hardening
Quench and temper.
480°C minimum temper.
7 Mechanical properties prior to
surface hardening. See also
item 144), 5)
28 HRC minimum. Other mechanical testing is required only if specified.
8 Microstructure prior to surface
hardening2)
Not specified. Sound metallurgical practice dictates that the core microstruc-
ture requirements are maintained in the tooth area to a depth
twice the minimum specified effective case depth or 2.5 mm,
whichever is less, below the minimum specified effective case
depth. The microstructure in this zone should be predominantly
tempered martensite that is free of blocky ferrite, pearlite, and
measurable bainite observable at 400--600X. Below this zone the
coremicrostructure should be primarily temperedmartensite and
free of blocky ferrite with the following limits:
Controlling section size, mm Non--martensitic
at least less than structures maximum
---- 127 10%
127 ---- Hardness must be obtained
at roots with 482° minimum
temper
9 Ultrasonic inspection3) Certification not required. 100% ultrasonic inspection in two (2) perpendicular directions,
per ASTM A388 is required, and the following limits apply:
-- No indications larger than 50% of the reference back reflec-
tion.
-- No continuous indications over an area larger than twice the
diameter of the search unit, regardless of amplitude.
-- No reflections that produce indications accompanied by a
50% loss of back reflection, not attributable to the geometric
configuration.
For pinions, above UT applies in radial direction, 360 degrees
around, and axially from both ends.
All test surfaces to be machined to a maximum of 6.2 mm surface
finish.
10 Overheating, especially at the
tooth tips and end faces
Avoid surface temperatures that result in grain growth, incipientmelting, or unfavorable resid-
ual stresses. Larger chamfers minimize this problem.
11 Tempering after surface
hardening
1 hour minimum at temperature. Furnace temper is required.
12 Surface hardness in tooth
area5)
Should meet the following characteristics when using only Rockwell mobile or Equotip hard-
ness testers:
50 HRC minimum 54 HRC minimum
Measurements are to bemadeonboth flanks of aminimumof four teeth locatedapproximate-
ly 90 degrees apart and shall spiral across the pinion face width.
13 Case depth considering subse-
quent stock removal. See also
item 19 5) 6) 7)
Should meet the characteristics of 13.1 and 13.2.
13.1 Effective case depth in finished
condition 6) 7)
Minimum effective case depth per figure 11.
(continued)
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
29© AGMA 2006 ---- All rights reserved
Table 8 (concluded)
Item Characteristic1) Grade M1
Type A (flank and root
hardening) only
Grade M2
Type A (flank and root hardening) only
13.2 Minimum effective case depth
minimum at root radius, or on
representative sample with
same geometry andmaterial as
work piece6)
Not specified. Verification not required. 50% of minimum specified effective
case at 1/2 tooth height above the root recommended.
14 Base hardness after surface
hardening. Seealso item74), 5),
6), 7)
28 HRC minimum.
15 Case microstructure consider-
ing subsequent stock removal
disregarding corner effects 6),
7), 8)
The first 20% of the casemicrostructure should be predominantly temperedmartensite. The
microstructure should be free of undissolved pearlite observable at 100X and measurable
bainite observable at 400 -- 600X.
The following case microstructure characteristics for each grade must be met.
15.1 Microstructure of case along
flank
Primarily fine acicular
martensite.
Primarily fine acicular tempered martensite. Non--martensitic
structures anywhere in the case should not exceed 5%.
15.2 Microstructure at root Primarily fine acicular
martensite.
Primarily fine acicular tempered martensite. Non--martensitic
structures anywhere in the case should not exceed 10%.
16 Heat affected zone. See also
item 13 6), 7)
Induction hardening heat treatments have a characteristic heat affected zone that is caused
by the surface heating process. This zone can have lower hardness and differentmicrostruc-
ture than the basematerial. The case depth specification should be established to avoid gear
failure which might initiate in this zone.
17 Surface temper etch inspection
of ground teeth
Not specified. Verification not required. Capable of meeting FB2 as defined in
ANSI/AGMA 2007--C00 is recommended.
18 100%magnetic particle inspec-
tion of finished teeth, roots and
other machined surfaces 3), 9)
Inspection to the following limits:
The magnetic particle technique per ASTM E1444 should use the true continuous method,
wet fluorescent or wet visible, with direct or indirect magnetization, in two directions.
No indications are permitted.
19 Visual inspection of the finished
pinion
Inspection to the following limits:
No linear indications, cracks, seams, laps or tears allowed.
20 Shot peening 10) Shot peening per SAE/AMS--S--13165 may be used to increase surface residual compres-
sive stress.
NOTES:
1) Metallurgical requirements assume homogeneous composition. In practice microsegregation and banding occurs in steels. This
microsegregation can produce variations in microstructure and properties that need to be assessed.
2)Grade requirements for non--metallic inclusion, and microstructure characteristics apply only to those portions of the gear material
where the teeth will be located to a depth below the finished tooth tip of at least 1.5 times the tooth height.
3) In--process ultrasonic and/ormagnetic particle inspection of gearing blanks is recommended for large diameter parts to detect flaws
before incurring the expense of further machining.
4) Mechanical properties including core hardness may not be the same after induction as they were before induction.
5) See ASTM A370, ASTM E140 or ISO 6336--5, annex C for hardness conversion tables.
6) See AGMA 923--A00, clauses 3 and 4 for a discussion on test coupons.
7) The hardness pattern, depth, facilities and process method must be established, documented and verified to be repeatable. Pro-
cess equipment and methods must be sufficiently accurate to reproduce the specified results. Excessive case depth can generate
unfavorable residual stress conditions.
8) Microstructure analysis of induction hardened test specimens have shown indications of undissolved pearlite or “ghost pearlite”.
This is especially true with rapid (short) heating cycles. This “ghost pearlite” should not be present.
9) Indications less than 0.4 mm are not considered.
10) It is recommended that ANSI/AGMA 2004--B89 be reviewed to determine if the benefits of surface residual compressive stress
achieved by shot peeningmay be beneficial to the particular application. Shot peening of the flanks of gear teeth should be reviewed to
ensure that no detrimental effects are caused to the gear set.
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
30 © AGMA 2006 ---- All rights reserved
Flank and root hardening
(tooth to tooth)
Inductor head
Type A
Figure 10 -- Hardening pattern obtainable on pinion teeth with induction hardening
0.25 2.5 25
N
o
rm
al
m
o
d
u
le
,m
n
Minimum effective case depth, mm
Induction hardened
0.51 0.76 1.27 1.78 5.1 7.6 12.7 17.8
127.0
84.7
50.8
36.3
12.7
8.5
25.4
Carburized
he= 0.10125.4mn 
−0.86105
he= 0.146925.4mn 
−0.86105
254.0
Figure 11 -- Minimum effective case depth for carburized and induction hardened pinions, he min
14 Momentary overloads
When the gear set is subjected to infrequent (less
than 100 cycles during the design life) momentary
high overloads approaching yield, the maximum
allowable stress is determined by the allowable yield
properties rather than thebending fatigue strengthof
the material. This stress is designated as σs .
Equation 24 calculates allowable yield strength for
through hardened steel.
σs= 3.14 HB− 214 (24)
where
HB is Brinell hardness of member (pinion or
gear), HB.
For a case hardened gear, the analysis of allowable
yield properties should include a stress calculation
through a cross section of the material. In lieu of a
cross section analysis, the use of material core
hardness values can be used.
In these cases of overload, the design should be
checked to make certain that the teeth are not
permanently deformed. When yield is the governing
stress, the stress correction factor is considered
ineffective for ductile materials and its effect should
be removed from the YJ factor calculation. This is
illustrated in equation 25.
A momentary overload can cause an unusual face
load distribution factor that will be influenced by the
gear blank configuration and its bearing support. A
review of the load distribution factormay be required
in this case.
14.1 Yield strength for steel pinions and gears
The calculation of yield strength must be applied at
the maximum peak load to which the gears are
subjected. Equation 25 uses a limit of 75% of the
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
31© AGMA 2006 ---- All rights reserved
allowable yield stress conforming to industry
practice.
0.75 σs≥ Fmax
KH
b mt YJ Kf
(25)
where
σs is allowable yield strength number, N/mm2;
Fmax is maximum peak tangential load, N;
mt is transverse metric module, mm;
b is net face width of narrowest member, mm;
KH is load distribution factor;
YJ is geometry factor for bending strength;
Kf is stress correction factor, see AGMA
908--B89.
= 6× 10
7 P
π ω1 dw1
(26)
Fmax=
1000 P
vt
= 2000 T
dw1
where
P is maximum peak power, kW;
T is maximum transmitted pinion torque, Nm.
14.2 Yield strength of spheroidal graphitic
(SG) iron gears
The calculation of yield strength must be applied at
the maximum peak load to which the gear is
subjected. Equation 27 uses a limit of 75% of the
allowable yield stress conforming to industry
practice.
0.75 σs≥ Fmax
KH
b mt YJ
(27)
The allowable yield stress number for SG iron is
defined as:
σs= 1.71 HB− 67.6 (28)
15 Stress cycle factors, ZN and YN
Stress cycle factors, ZNand YN, adjust the allowable
stress numbers for the required number of cycles of
operation. For the purpose of this standard the
number of stress cycles, nL, is definedas thenumber
ofmesh contacts, under load, of the gear tooth being
analyzed. AGMA allowable stress numbers are
established for 107unidirectional tooth load cyclesat
99 percent reliability. The stress cycle factor adjusts
the allowable stress numbers for design lives other
than 107 cycles.
The stress cycle factor accounts for the S--N
characteristics of the gear material as well as for the
gradual increased toothstresswhichmayoccur from
tooth wear, resulting in increased dynamic effects
and from shifting load distributions which may occur
during the design life of the gearing.
15.1 Load cycles
Whenevaluating gearing, it is important to knowhow
many stress cycles the individual gears will experi-
ence during the intended life of the equipment.
Some installationswill run twenty--four hours per day
and operate for twenty or more years. Other
installations have gears that have a stress cycle
equivalent to a few hours. The gear designer should
design for the stress cycles that are appropriate for
the application. The number of stress cycles, nL, is
used to determine the stress cycle factor as follows:
nL= 60 L ω q (29)
where
nL is the number of stress cycles;
L is life (hours);
ω is speed (rpm);
q is number of contacts per revolution. (i.e.,
q = number of pinions per gear)
The design life should be set at 219,000 hours (25
years). This life will provide consistency with
previous standards. Other values of design life can
be used based on equipment type or contractual
agreement.
15.2 Stress cycle factors for steel and SG iron
gears
The stress cycle curves for pitting resistance and
bending strength of steel and SG iron gears are
shown in figures 12 and 13.
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
32 © AGMA 2006 ---- All rights reserved
0.5
0.6
0.7
0.8
0.9
1.0
2.0
3.0
4.0
5.0
102 103 104 105 106 107 108 109 1010
Number of load cycles, nL
ZN = 2.466 nL--0.056
Surface hardened
ZN = 1.8902 nL--0.03951.1
S
tr
es
s
cy
cl
e
fa
ct
or
,Z
N
Through hardened
ZN = 2.2496 nL--0.0503
Figure 12 -- Steel and spheroidalgraphitic iron pitting resistance stress cycle factor, ZN
0.5
0.6
0.7
0.8
0.9
1.0
2.0
3.0
4.0
5.0
Number of load cycles, nL
102 103 104 105 106 107 108 109 1010
0.5
0.6
0.7
0.8
0.9
1.0
YN = 1.6831 nL--0.0323
YN = 2.3194 nL--0.0538
S
tr
es
s
cy
cl
e
fa
ct
or
,Y
N
Figure 13 -- Steel and spheroidal graphitic iron bending strength stress cycle factor, YN
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--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
33© AGMA 2006 ---- All rights reserved
Annex A
(informative)
New equipment installation and alignment
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
A.1 Purpose
The gear and pinions covered by this standard are
generallymountedon supports that are independent
from each other, and their alignment is achieved
through field adjustments. The operating peak tooth
loads can exceed those calculated by the method of
this standard if these adjustments are not properly
conducted and maintained. This annex provides
installation and alignment guidelines that have been
found generally satisfactory when gears are rated
using AGMA Standards.
A.2 Gear installation
The ringgear is demountableand itmust beadjusted
during installation such that it is round, and that its
axis of rotation coincides with the axis of rotation of
the equipment, both radially and axially. This is
normally done by turning the equipment at slow
speed while measuring the radial and axial runout of
the gear using dial indicators. Proper measuring
techniques must be used to ensure that movements
recorded are separated from the movement of the
equipment itself, such as axial float.
In most cases, radial and axial measurements will
not be taken on the teeth themselves, but on
referencemachined surfaces, such as gear rim face
and gear outside diameter. It is therefore important
for the gear manufacturer to provide surfaces of
reference that are representative of the position of
the teeth. These surfaces must be controlled for
runout on the gear cutter prior to finish cutting the
gear teeth.
The radial runout relates to consistency of tooth
depth engagement. Changes in radial runout will
affect the uniformity of rotational speed. Its impor-
tance is, in large part, a function of speed, and
allowable values are therefore increased on slower
equipment. Axial runout relates to the uniformity of
the contact pattern. The axial runout relation to tooth
load is independent of rotational speed. Most gear
and equipment manufacturers have published al-
lowable values for axial and radial runout, and gears
must be installed within the limits specified.
A.3 Pinion positioning
When the gear installation is complete, the pinion
must be positioned in mesh with the gear at the
correct depth of engagement. This is accomplished
by installing the pinion with the appropriate values of
backlash and root clearance.
The gearing should be installed to the supplier’s
specified backlash range. Insufficient backlash will
lead to back flank contact or, in some cases, tip to
root interference. Too much backlash will reduce
working depth and tooth overlap, which will increase
tooth loading. The following factors have to be
considered when determining the required amount
of backlash:
-- size of teeth;
-- expected thermal growth of gear and pinion;
-- expected change in center distance due to ther-
mal growth of the equipment and supports;
-- expected change in center distance due to wear
on equipment bearings or supports;
-- expected gear radial runout in operation.
Ona newgear set, adjusting for backlash is normally
the preferred method to position the pinion. Root
clearances should also be measured and recorded
for reference purposes.
Reference diameters are often scribed on the side of
the gear and pinion teeth. These scribed lines are
normally designed such that they should be tangent
or slightly separated at installation, but never over-
lapping unless specified by the supplier. They
provide a useful aid at installation, but they should
not be viewed as a replacement to backlash and root
clearance measurements. Care must be taken
when using scribe lines if elements from different
manufacturers are meshed, since not all manufac-
turers locate the scribe at the same diameter.
A.3.1 Worn elements
With worn gear or pinion or both tooth flanks, root
clearances should be used, as tooth wear canmake
backlash readings an unreliable indication of true
pinion position. Installing a replacement pinion
deeper in mesh than the previous pinion should
never bedone. This is due to the fact that awear step
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
34 © AGMA 2006 ---- All rights reserved
may have developed at the root of the gear tooth
profiles. If only backlash readings are used, due to
thewear of the prior installation, the pinionwill be set
too deep. For this reason, root clearances should
always bemeasured prior to removing an old pinion.
The root clearances should be measured at the root
of the gear rather than at the root of the pinion, as
root diameters can vary significantly from one pinion
to another depending on the tooth manufacturing
method.
A.4 Alignment
Alignment is the adjustment made to the position of
the pinion (or the gear or both on single pinion
machines) in order to get equal tooth load at both
ends of the tooth face.
A.4.1 Static alignment
A static alignment is first done based on measure-
ments taken while the equipment is at rest. This is
accomplished by measuring the clearance on the
contact and backlash flanks of meshing teeth using
feeler gauges. Adjustments are made to get equal
readings at both ends of the face. Prussian blue or
equivalent media is used to visualize the tooth
contact under no load condition. On dual rotation
equipment, all meshing flanks must be measured
and considered.
The readings must be recorded at a sufficient
number of stations around thegear to be representa-
tive of an expected gear axial runout pattern. The
final position of the pinion is the location that
averages out the readings noted at each station.
The alignment may be slightly biased towards one
side by a predetermined amount, as dictated by
experience, due to loading or temperature.
A.4.2 Dynamic alignment
Most pinions have to be realigned after start--up to
correct for dynamic effects such as pinion deflection
(torsional and bending -- see annex C), deflection of
the gear body under radial and thrust load, deflection
of the mill or kiln, pinion movement due to bearing
clearances, thermal deformations, and other dy-
namic factors having an effect on the alignment.
For equipment of slower speed, such as kilns or
dryers, where themesh does not generate sufficient
heat to obtain a significant temperature differential,
the need for realignment is based on visual observa-
tion of the pinion flanks. The use of amarking dye to
paint some teeth before operation can be used as an
aid to evaluate the alignment.
On faster rotating equipment, such as grindingmills,
the need for pinion realignment after start--up is
based on the difference between the operating
temperatures measured at both ends of the pinion
face. The pinion temperature can be measured in
operation using an infrared thermometer. Experi-ence has shown that, on unidirectional equipment, a
temperature differential of 8°C or less between both
ends of the pinion teeth is satisfactory for long term
operation. Higher temperature differentials require
realignment. Consult manufacturer for additional
guidance.
For double helical gears, the pinion temperature
differential must be measured and evaluated inde-
pendently for each helix. If both helixes have
dissimilar temperature differential, the best align-
ment will be a compromise between both helixes.
For bi--directional rotation equipment, the tempera-
ture differential in both directions of rotation must be
known prior to realigning the pinion. Note that it is
common for the temperature differential to fluctuate
with time, due to periodic load variation among other
effects, and it is therefore often necessary to
establish a nominal range of operating temperatures
before realigning. This effect is more noticeable on
high power, bi--directional equipment. Temperature
differential of 11°C or less between both ends of the
pinion teeth is generally viewed as satisfactory for
long term operation.
Because of the empirical nature of the relationship
between temperature differential and physical ad-
justments, it is typical to make more than one pinion
move prior to reaching satisfactory alignment. It is
critical to the gear and pinion integrity that the site
allows the necessary equipment down time to
conduct these adjustments.
Note that when the initial static alignment is con-
ducted accurately, subsequent adjustments re-
quired at the pinion are generally small enough for
the drive train couplings to stay within their angular
and offset alignment limits. Nevertheless, these
should always be taken into consideration when
making corrections to mesh alignment. After final
adjustment, backlash and tip--to--root clearance of
the pinion must be reviewed and recorded.
A.4.3 Maintaining alignment
Pinion alignmentwill changewith timedue to several
factors such as bearing wear, tooth wear, significant
changes in loading, and foundationmovements. It is
imperative that pinion alignment be maintained with
time and it should bemonitored on a regular basis as
a part of a regularmaintenanceprogram. Seeannex
G.
Copyright American Gear Manufacturers Association 
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
35© AGMA 2006 ---- All rights reserved
Annex B
(informative)
Drive characteristics -- Multiple pinion drives
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
B.1 Purpose
The gear designer should be aware of the more
common types of motor drives used on cylindrical
shell and trunnion mounted equipment, and the
following is a discussion of these drives. It should be
understood that load sharing on multiple pinion
drives is rarely perfect and design allowances have
to bemade for equipment operatingwhen the load is
not shared equally between the drives.
B.2 Constant speed dual pinion drives
B.2.1 Wound rotor motor drives
Wound rotor motors controlled by liquid rheostats
provide smooth acceleration while keeping the
accelerating torque of the two motors balanced.
After obtaining rated speed the liquid rheostats are
bypassed by rotor circuit contactors. Because
wound rotor motors have large inherent slip, auto-
matic load sharing at full speed is obtained.
However, any minor load imbalance can easily be
corrected by the insertion of a small resistor bank in
one of the motor rotor circuits.
Advantages:
-- excellent load sharing during starting and at
constant speed operation;
-- torque transmission to the gears is soft.
Disadvantages:
-- special liquid rheostat designs are required to
prevent large torque transients during liquid
rheostat bypass switching operations.
B.2.2 Synchronous motor drives
Synchronous motors have been used extensively to
drive single pinion equipment because motor
speeds can easily be matched to pinion speeds.
However, because synchronous motors cannot
provide adequate torque to start loaded equipment,
a clutch is required. This allows the motor to be
started unloaded and after it is running at rated
speed, it is capable of providing the required torque
to start the equipment. This method works well with
singlepiniondrives, but as soonasasecondmotor is
added todrive theequipment, load sharingproblems
are encountered because the stator/rotor pole
alignment of the two motors cannot be perfectly
matched.
Electrical equipment manufacturers have tried sev-
eral solutions by interconnecting statorwindingsand
exciter field forcing schemes, but most have been
found to be unsatisfactory. However, one successful
design employs a load sharing system using air
operated clutches anda rotor pole face fieldwinding.
The clutches are used to accelerate the equipment
and, at rated speed, the load share regulator is
engaged. By pulsing the clutches, the motor loads
are equalized to within plus or minus a few percent-
age points. Then, by adjustment of rotor pole face
winding excitation, motor loads are balanced.
Advantages:
-- high drive efficiencies are possible due to the
use of low speed synchronous motors, which
are directly coupled to the pinion gears;
-- power factor correction is possible.
Disadvantages:
-- multiple pinion drives require load share regula-
tors;
-- drive line resonance is possible.
-- clutches are required.
B.3 Adjustable speed dual pinion drives
B.3.1 Liquid rheostat wound rotor motor drives
The same equipment is used as described in B.2.1
above, except the liquid rheostat requires a large
heat exchanger, or cooling tower, to transfer the
motor slip power which occurs when the equipment
runs at reduced speed. These power losses can be
as high as 10% of the motor rating.
Advantages:
-- initial investment is low;
-- torque transmission to the gears is soft.
Copyright American Gear Manufacturers Association 
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Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
36 © AGMA 2006 ---- All rights reserved
Disadvantages:
-- a very accurate liquid rheostat is required to
keep the two motor loads balanced;
-- special liquid rheostat design is required to pre-
vent large torque transients during liquid rheo-
stat bypass operation;
-- liquid rheostat andheatexchangermaintenance
is high;
-- operating costs are high due to power losses.
B.3.2 Slip energy recovery wound rotor motor
drives
Instead of wasting the slip power as heat it can be
rectified and returned to the power grid. This drive
technology has only been applied to single pinion
drives because torque pulses generated as a result
of power conversion can create a drive line reso-
nance when used with dual pinion drives.
Advantages:
-- improves drive efficiency;
-- low cost.
Disadvantages:
-- driveline resonance may develop at specific op-
erating speeds;
-- a liquid rheostat is required in addition to the slip
recovery controller.
B.3.3 Cycloconverter powered dual pinion
synchronous motor drives
The driveline of this drive is identical to B.2.2 above
except that equipment acceleration is achieved by
cycloconverter control and not by the use of
clutches. Therefore, themotor exciter can no longer
be of a brushless type because rated motor field
excitation is required over the entire acceleration
and operatingspeed range. The cycloconverter
controller is of identical design as used on gearless
equipment drives and, therefore, generates the
same harmonics. The drive also requires a fairly stiff
grid power supply.
Advantages:
-- initial investment cost is lower than a gearless
drive.
Disadvantages:
-- harmonic filter and power factor correction
equipment is required;
-- on power supply outage, the risk of gear or pin-
ion damage exists, which can be prevented by
the addition of clutches set to slip at 150%ofmo-
tor torque.
B.3.4 Load commutated inverter (LCI) dual
pinion synchronous motor drives
Only a very few LCI drive applications exist. This
drive requires a clutch for equipment starting be-
cause at near zero speed themotor is not capable of
developing the required starting torque. Therefore,
the motor is started with the clutch disengaged, and
after the motor is above 10% of rated speed, the
clutch is engaged to accelerate the equipment to the
motor speed. After the clutch has locked up, the LCI
controller brings the equipment to rated speed. LCI
converter commutation causes torque pulses and
these pulses are greatest at reduced speeds.
Advantages:
-- initial investment cost is lower than for a cyclo-
converter drive;
-- power converter harmonic spectrum is less
complex than that for the cycloconverter.
Disadvantages:
-- LCI converter generated torque pulses may
cause drive line resonance;
-- clutches are required.
B.3.5 Direct current motor drives
Direct current (DC) drives provide smooth accelera-
tionwhile keeping themotor torque balanced. Direct
current power is furnished by thyristor controlled
converters connected to step down transformers.
Themotor speed is generally the same as the pinion
speed. Thedrivecontroller accuratelybalances load
torque and the drive is capable of supplying rated
torque over the entire base speed range (usually
zero to 74% of critical speed for grinding mills).
Therefore, direct current drives can be used for
inching the equipment. Above base speed the drive
operates at constant power.
Advantages:
-- drive has excellent speed and torque control;
-- no inching drive is required;
-- drive reversal is simple;
-- power converter harmonic spectrum is less
complex.
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
37© AGMA 2006 ---- All rights reserved
Disadvantages:
-- initial investment is high;
-- drive efficiency is low;
-- harmonic filter and power factor correction
equipment is required;
-- in the event of DC motor flash over, the risk of
gear and pinion damage exists, which can be
prevented by addition of clutches set to slip at
150% of motor torque.
B.4 Summary
Various methods can be employed to address the
different drive characteristics discussed above.
Requiring higher service factors or increased indi-
vidual component ratings are two typical methods
used to compensate for drive characteristics.
It should be noted that proper pinion to gear
alignment is important in all cases. However, it
becomes critical for multiple pinion drives on bi--
directional driven equipment.
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
38 © AGMA 2006 ---- All rights reserved
Annex C
(informative)
Rim thickness/deflection
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
It is the responsibility of the gear designer to ensure
the stress and deflection of the entire gear structure
(pinion and gear) is suited to the application. This
includes, but is not limited to, ensuring the gear rim
deflection is within acceptable limits for the applica-
tion, see figures C.1 and C.2. Specific allowable
values and formulas are not provided due to the
complexity of the calculations. To validate the
design, the purchaser and gear designer should
mutually establishwhichcalculationmethodsshould
be used. These may include historical data, finite
elementanalysis, provenempirical design rules, and
classical calculations.
Issues to be considered include:
-- reduction of strength rating by moving the loca-
tion of bending fatigue failure into the gear rim
from the tooth root (KBm factor);
-- effect of rim deflection on the load distribution
factor, KH;
-- influence of themating element on load distribu-
tion factor, KH, see figure C.3;
-- definition of dynamic alignment techniques to
achieve correct mesh patterns.
Overhang
deflection
Factors to be considered
include:
-- load
-- face width
-- rim thickness
-- stiffener spacing
-- window size
-- number of windows
-- support web thickness
-- material
Figure C.1 -- Tee section gearing
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
39© AGMA 2006 ---- All rights reserved
Factors to be considered
include:
-- load
-- face width
-- rim thickness
-- stiffener spacing
-- window size
-- number of windows
-- box width
-- material
Deflection
center
Overhang
deflection
Box width
Figure C.2 -- Box (Y or delta) section gearing
Factors to be considered include:
-- load
-- face width
-- bearing span
-- shaft diameters
-- tooth size
Bending
X1
X2
X3
X4
X5
d
Torque
inputTorsional
deflection
Li Load on teeth
L1
L2
L3
L4
L5
L6
din
Torque
input
Facewidth
Undeformed
position
Figure C.3 -- Pinions
Copyright American Gear Manufacturers Association 
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Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
40 © AGMA 2006 ---- All rights reserved
Annex D
(informative)
Open gearing lubrication
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
D.1 Purpose
This annex provides a brief description of lubricant
types and applicationmethods. Themajority of gear
surface distress problems (such as wear, scoring, or
spalling) occur due to lubrication related issues. The
correct type and application of lubricant is critical to
the long term service life of gearing. The lubricant
type and delivery method must be compatible.
Issues include:
-- contamination -- airborne, ingress, entrapped in
lubricant;
-- inadequate quantity;
-- improper frequency;
-- improper application;
-- improper drainage;
-- lubricant type and grade.
The gear manufacturer’s recommendations should
be followed.
D.2 Lubricant types
The selection of lubricant depends upon the specific
application where the size of the gear, the trans-
mitted power, the speed of the gear, the ambient
temperature, airborne contaminants, and the sur-
face finish of the gearing all must be taken into
account. The following descriptions are common in
the literature.D.2.1 Residual compounds
A viscous mixture of petroleum based compounds,
also referred to as asphaltics. Most residual
compounds use nonchlorinated diluents to provide
pumpability. Most contain extreme pressure (EP)
additives or friction modifiers (solid lubricants) such
as graphite or molybdenum disulfide.
This type of lubricant has been used successfully for
years. It is thick, has a high viscosity, 645 cSt and
higher at 99°C, and usually needs a diluent to aid in
its application. The base product is heavy and
tenacious (stays in place). Residual compounds
operate on the principle of an oil film separating the
surfaces of the gear and pinion. An environmental
development concerning diluents is that trichloroe-
thylene based diluents are no longer permitted to be
used due to ecological and health reasons. Some
replacement diluents do not “flash off” as quickly as
the old diluents, and therefore, more frequent
applications may not provide the expected
protection.
Advantages:
-- high viscosity;
-- diluents allow cleaner spray nozzles, aid flow,
and allow lower temperature pumping;
-- newer base stocks no longer build up in the tooth
roots and on the gear guard;
-- residuals provide extended lubrication film reten-
tion;
-- spent product drains freely from gear guards.
Disadvantages:
-- replacement solvents have a lower flash point;
-- more frequent application may wash off lube;
-- requires air purge of nozzles to prevent clogging.
D.2.2 Oils
Either petroleum based (R&O), EP, or synthetic oils
with or without EP additives. These products also
operate on the principle of an oil film separating the
surfaces of the gear and pinion. These oils are
applied in much the same way as residual com-
pounds.
Advantages:
-- diluents are not generally needed to aid flow of
lubricant;
-- high viscosity;
-- no buildup tendency in tooth roots or on gear
guard;
-- drains freely from gear guards.
Disadvantages:
-- heat tracinganddrumheatersmaybe required to
obtain proper spray pattern;
-- annual usage cost may be higher.
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Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
41© AGMA 2006 ---- All rights reserved
D.2.3 Compounds
A synthetic or petroleum base oil with friction
modifiers and EP additives. Some contain a diluent
for pumpability. Many have polymer additives as
viscosity enhancers. Some have thixotropic proper-
ties where the viscosity of the lubricant changeswith
the pressure experienced during operation. These
products utilize friction modifiers to assist their
thinner load carrying oil films. These products are
applied in much the same way as residual com-
pounds and oils, above.
Advantages:
-- the friction modifiers can be viewed as a safety
margin in addition to the oil film;
-- friction modifiers can provide protection at start--
up or very slow speeds.
Disadvantages:
-- thinner oil film;
-- more difficult to pump;
-- marginal elastohydrodynamic (EHD) oil film;
-- harder to drain from gear guard.
D.2.4 Greases
Petroleum based or synthetic oils to which soap
thickeners or carriers are added. Friction modifiers
(typically, graphite and molybdenum disulfide) and
EP chemicals are usually added. Some have
thixotropic properties where the viscosity of the
lubricant changes with the pressure experienced
during operation.
The group of products listed in D.2.1 through D.2.3
has been successful over the years. They are based
on the philosophy that the lubricant itself must have
adequate viscosity. This is needed to: 1) stay in
place (tenacious), and 2) provide film thickness,
when under pressure, to ensure that no contact
takes place between mating tooth surfaces. An
alternate method is to employ base oils of lower
viscosity blendedwith thickenersandadditives (e.g.,
friction modifiers and chemical EP’s). The blended
lubricant is typically not as tenacious as the lubri-
cants listed above, but it has been adequate
lubricating the tooth surfaces on numerous applica-
tions. Additives in greases allow the gear and pinion
surfaces to operate in near boundary lubrication
conditions, where the oil film thickness is small and
the surface asperities of the gear and pinion may
come in contact. This can be controlled by the use of
run--in compounds.
Advantages:
-- diluents are not generally needed to aid flow of
lubricant;
-- may have better low temperature pumping char-
acteristics with 0 or 00 grades.
Disadvantages:
-- necessitates use of run--in compounds;
-- application rates are more frequent, with less
volume;
-- total usage may be greater than other products;
-- marginal film thicknesses;
-- lubricant builds up on gear guard sides;
-- annual usage cost may be higher.
D.3 Use of run--in compounds
Run--in compounds are typically used to prepare a
new gear set to be lubricated by a grease type
product, but are not required if the viscosity of the
lubricant is high enough to keep the gear and pinion
separated.
Lubrication is to keep surfaces apart during opera-
tion. A measure of the separation of surfaces [3] is
specific film thickness, λ, which is a ratio of fluid film
thickness, h, to the composite roughness of the
driver and the driven gears, σ. The parameters that
influence h are geometry, load, speed and lubricant
viscosity.
In any fixed situation, to get the desired λ, there are
only a few possible variations. Geometry, speed,
and load are usually fixed due to operational
concerns, and cannot be changed easily, leaving
viscosity and surface finish as variables. One can
either increase viscosity, improve surface finish, or
both. A running--in compoundsmooths thesurfaces,
reducing σ, thereby increasing λ. A running--in
compound therefore assists in making a lower
viscosity lubricant a more viable alternative.
Grease type lubricants typically benefit from the use
of run--in compounds to improve surface finish. As
gear rims often are quite large and, as hardnesses
vary, the tooth flanks can be rough, wavy, or not
dimensionally constant. The initial contact on a gear
face, even when the pinion(s) and the driven gear
are properly aligned,mayoccasionally be in thearea
of 50--60%. This means that when putting new gear
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
42 © AGMA 2006 ---- All rights reserved
drives into operation (during the run--in period) there
is the danger of partially overloading the tooth
flanks, which could result in damage (initial pitting,
local scuffing) thatmight develop intomajor damage
during operation. Run--in compounds are intended
to improve surface finish only and not overall quality
of the gear set.
Typically, for gear drives utilizing grease lubrication,
to avoid “initial damage” it is necessary to start out
with a running--in lubricant prior to operation under
full load. This is essentially a mild chemical etchant,
activated by pressure and temperature, which
removes asperities. Running--in refers to intention-
ally producing very limited wear at the tooth flanks,
andat thesame timeprotects themagainst adhesion
and scuffing to avoid initial damage. Surface
roughness may be reduced within a short period of
time, and waviness or form errors may be compen-
sated for to achieve better load distribution.
Consult the gear manufacturer before using run--in
compounds regarding the impact on any tooth
modifications.
D.3.1 Worn gear sets
In caseswhere the operational surfaces of a gear set
are damagedregardless of cause, a different
procedure is used. A more aggressive running--in
compound can smooth the mating surfaces to
increase mating surface area. Given that the
operational loads are nowborne over a greater area,
stresses are reduced, buying time to learn the cause
of the damage and then prevent it from recurring.
This procedure can be used for a short--term
extension of gear component life, and to reduce
significant vibrations emanating from thegearmesh.
High surface variations in the areas of spalls and
wear steps may need to be reduced by additional
mechanical dressing prior to the application of the
run--in compound. It should be noted that this
procedure precludes the future replacement of
individual gear elements. A complete gear set
reversal or replacement will eventually have to be
installed.
In the event a new pinion (especially if surface
hardened) is to be fitted to an old or damaged gear, a
more aggressive run--in compound may also be
used. In some cases the damaged gear areas may
have to be hand dressed. Again, eventually the
complete gear set would have to be reversed or
replaced.
Consult the gear manufacturer before using run--in
compounds regarding the impact on any tooth
modifications.
D.4 Application methods
D.4.1 Intermittent spray
An intermittent spray system delivers new lubricant
at programmed intervals, 1.5 to 25minutes, depend-
ingon the lubricant. This systemcandeliver all types
of lubricant. Generally, greases should be applied to
the pinion at intervals from1.5 to 5minutes. All other
lubricants should be applied to the gear in intervals
from 10 to 25minutes. No interval should exceed 25
minutes. Using an intermediate interval (e.g., 15
minutes) as a starting point, temperature profiles,
contacts, and surface conditions are used as infor-
mation to adjust future lubricant application. As time
passes, temperature profiles are monitored, the
tooth surfaces are observed using a strobe light,
and, during shutdowns, the teeth are cleaned and
any surface discontinuities on the teeth are evaluat-
ed. All of these are used to evaluate how well the
lubricant is working and how its application might be
adjusted. The gear guard, feed lines and lubricant
may have to be heated to be able to deliver the
lubricant.
D.4.2 Idler immersion (oiling pinion)
This technique is commonly used on slow speed
applications such as kilns and dryers. Oils and
compounds are the typical lubricants used in this
technique. The lubricant must be maintained at a
minimum temperature to avoid channeling of the
lubricant. One of the advantages of this technique is
low system maintenance. The lubricant must be
monitored for debris and water. Debris can cause
damage to the surfaces of the driving and driven
gear, and water can reduce the viscosity in the
lubricant reservoir, rendering the lubricant
ineffective.
D.4.3 Continuous lubrication
In this case, the lubricant is sprayed or dripped into
the mesh. It is collected in the bottom of the gear
guard, conditioned (filtered), and recirculated to be
used again. The gear guard must have an effective
seal to keep contamination from the lubricant and to
prevent leakage. Because the flow of the lubricant is
crucial to the effectiveness of a continuous system,
the lubricant may have to be heated to ensure
fluidity.
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
43© AGMA 2006 ---- All rights reserved
D.5 Summary and further reading
The quantity of the different types of lubricant to limit
the probability of wear is beyond the scope of this
introductory Annex. Dowson and Toyoda [3] devel-
oped an equation for the central EHD film thickness
that accounts for the exponential increase of the
lubricant viscosity with pressure, tooth geometry,
velocity of the gear teeth, elastic properties of the
materials and the transmitted load. The film
thickness determines the operating regime of the
gear set and has been found to be a useful index of
the wear related distress probability. Wellauer and
Holloway [4] also found that the specific film
thickness could be correlated with the probability of
toothsurfacedistress. Readersaredirected to these
references. Other data may be found in AGMA
925--A03andAGMA9005--E02, clause6andAnnex
D.
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
44 © AGMA 2006 ---- All rights reserved
Annex E
(informative)
Sample problems
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
E.1 Purpose
This annex provides several example power rating calculations, using the methods described in ANSI/AGMA
6114--A06.
E.2 Application ball mill single pinion
P = 2800 kw
CSF = 1.500
KSF = 2.25
ω1 = 200 rpm
b = 710 mm
Np = 21
Ng = 295
tR = 68.5 mm
ht = 57.1 mm
HR1 = 55 HRC
HB2 = 245 HBN
Av = 9
βs = 6.800 deg
φn = 25 deg
L = 219000 hours
q = 1
mn = 25.4 mm
x1 = 0
x2 = 0
dO1 = 587.98 mm
dO2 = 7596.9 mm
Modified leads
Bearing supported mill
Steel material grade M2
a = 4041.635 mm
ZE = 190 (N/mm2)0.5
E.2.1 Calculations
= 14.0476
u=
Ng
Np
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
45© AGMA 2006 ---- All rights reserved
= 537.179 mm
dw1=
2 a
u+ 1
= 25.5799 mm
mt=
mn
cos π180 βs
= 1.2
mB=
tR
ht
= 1
KBm= − 1.788 mB+ 2.7636 if mB< 1.0
1.0 otherwise
ZI = 0.2683
YJ1 = 0.6058
YJ2 = 0.7044
= 0.6716
Bmill=
12−17− Av− (11−Av)210 
0.667
4
= 68.3893
Cmill= 50+ 56 1− Bmill
= 5.6253 m∕sec
vt=
π ω1 dw1
60000
= 1.3051
Kvm=Cmill+ 196.85 vtCmill 
Bmill
= 565.1858
HB1= 6.96608 10−2 +⎪
⎡
⎣
1.0
− 9.6806310−5 − 1.6255210−9H3
R1
 + 0.117524HR1
⎪
⎤
⎦
HB1
HB2
= 2.3069
0.00967 otherwise
A= 0 if
HB1
HB2
< 1.2
0.00898 HB1
HB2
− 0.00829 if 1.2≤ HB1
HB2
≤ 2.0
= 0.0097
= 1.1262
ZW= 1+ A (u− 1)
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
46 © AGMA 2006 ---- All rights reserved
KHmc = 0.95
KHpm = 1.0
KHe = 0.8
b
10 dw1
− 0.1109+ 0.000815 b− 0.000000353 b2 otherwise
KHpf=  b10 dw1− 0.0375+ 0.000492 b if b≤ 432
= 0.4223
A = 1.27× 10--1
B = 0.622× 10--3
C = --1.69× 10--7
= 0.4834
KHma= A+ B b+ C b
2
= 1.7683
KHβ= 1.0+ KHmc KHpf KHpm+ KHma KHe
KH= KHβ
σHP1 = 1450 N/mm2
σFP1 = 425 N/mm2
= 825.715 N∕mm2
σHP2= 2.407 HB2+ 236
= 285.235 N∕mm2
σFP2= 0.703 HB2+ 113
= 2.628× 109
nL= 60 L ω1
1.8902 n−0.0395L  otherwise
ZN1= 1.2942 if nL< 10
4
= 0.8025
2.466 n−0.056L  if 104≤ nL≤ 107
1.6831 n−0.0323L  otherwise
YN1= 1.5995 if nL< 10
3
= 0.8353
2.3194 n−0.0538L  if 103≤ nL≤ 3× 106
= 1.8708× 108
nL= 60 L ω1u  q
2.2496 n−0.0503L  otherwiseZN2= 1.2942 if nL< 10
4
= 0.863
2.466 n−0.056L  if 104≤ nL≤ 107
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
47© AGMA 2006 ---- All rights reserved
1.6831 n−0.0323L  otherwise
YN2= 1.5995 if nL< 10
3
= 0.9098
2.3194 n−0.0538L  if 103≤ nL≤ 3× 106
= 9335
Pazm1=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP1 ZN1
ZE
2
= 4450
Pazm2=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP2 ZN2 ZW
ZE
2
= 9521
Paym1=
π ω1 d1
6× 107 Kvm
b mt YJ1 σFP1 YN1
KH KBm
= 8092
Paym2=
π ω1 dw1
6× 107 Kvm
b mt YJ2 σFP2 YN2
KH KBm
= 2967 hp
Pa= minPazm1CSF , Pazm2CSF ,
Paym1
KSF
,
Paym2
KSF

E.3 Application kiln single pinion
P = 90 kw
CSF = 1.022
KSF = 1.788
w1 = 18 rpm
b = 330 mm
Np = 17
Ng = 192
tR = 68.6 mm
ht = 57.2 mm
HB1 = 363 HB
HB2 = 269 HB
Av = 9
βs = 0 deg
φn = 20 deg
L = 219000 hours
q = 1
mn = 25.4 mm
x1 = 0.50
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
48 © AGMA 2006 ---- All rights reserved
x2 = -- 0.50
dO1 = 508 mm
dO2 = 4902.2 mm
Unmodified leads
Roller supported mill
Steel material grade M2
a = 2654.3 mm
ZE = 190 (N/mm2)0.5
E.3.1 Calculations
= 11.2941
u=
Ng
Np
= 431.8 mm
dw1=
2 a
u+ 1
= 25.4 mm
mt=
mn
cos π180 βs
= 1.2
mB=
tR
ht
= 1
KBm= − 1.788 mB+ 2.7636 if mB< 1.0
1.0 otherwise
ZI = 0.1549
YJ1 = 0.4688
YJ2 = 0.3751
= 0.6716
Bmill=
12−17− Av− (11−Av)210 
0.667
4
= 68.3893
Cmill= 50+ 56 1− Bmill
= 0.407 m∕s
vt=
π ω1 dw1
60 000
= 1.0861
Kvm=Cmill+ 196.85 vtCmill 
Bmill
HB1
HB2
= 1.3494
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
49© AGMA 2006 ---- All rights reserved
0.00698 otherwise
A= 0 if
HB1
HB2
< 1.2
0.00898 HB1
HB2
− 0.00829 if 1.2≤ HB1
HB2
≤ 1.7
= 0.0038
= 1.0394
ZW= 1+ A (u− 1)
KHmc = 1
KHpm = 1.0
KHe = 0.8
b
10 d1
− 0.1109+ 0.000815 b− 0.000000353 b2 otherwise
KHpf=  b10 d1− 0.0375+ 0.000492 b if b≤ 432
= 0.2015
A = 2.47× 10--1
B = 0.657× 10--3
C = --1.186× 10--7
= 0.4512
KHma= A+ B b+ C b
2
= 1.5622
KHβ= 1.0+ KHmc KHpf KHpm+ KHma KHe
KH= KHβ
= 1109.741 N∕mm2
σHP1= 2.407 HB1+ 236
= 368.189 N∕mm2
σFP1= 0.703 HB1+ 113
= 883.483 N∕mm2
σHP2= 2.407 HB2+ 236
= 302.107 N∕mm2
σFP2= 0.703 HB2+ 113
= 2.3652× 108
nL= 60 L ω1
2.2496 n−0.0503L  otherwise
ZNp= 1.2942 if nL< 10
4
= 0.8529
2.466 n−0.056L  if 104≤ nL≤ 107
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
50 © AGMA 2006 ---- All rights reserved
1.6831 n−0.0323L  otherwise
YNp= 1.5995 if nL< 10
3
= 0.9029
2.3194 n−0.0538L  if 103≤ nL≤ 3× 106
= 2.0942× 107
nL= 60 Lω1u  q
2.2496 n−0.0503L  otherwise
ZNg= 1.2942 if nL< 10
4
= 0.9635
2.466 n−0.056L  if 104≤ nL≤ 107
1.6831 n−0.0323L  otherwise
YNg= 1.5995 if nL< 10
3
= 0.9764
2.3194 n−0.0538L  if 103≤ nL≤ 3× 106
= 131
Pazm1=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP1 ZN1
ZE
2
= 115
Pazm2=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP2 ZN2 ZW
ZE
2
= 313
Paym1=
π ω1 dw1
6× 107 Kvm
b mt YJ1 σFP1 YN1
KH KBm
= 223
Paym2=
π ω1 dw1
6× 107 Kvm
b mt YJ2 σFP2 YN2
KH KBm
= 112 kw
Pa= minPazm1CSF , Pazm2CSF ,
Paym1
KSF
,
Paym2
KSF

E.4 Application ball mill single pinion
P = 2575 kw
CSF = 1.50
KSF = 2.5
ω1 = 153.6 rpm
b = 760 mm
Np = 25
Ng = 234
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
51© AGMA 2006 ---- All rights reserved
tR = 68.6 mm
ht = 57.2 mm
HB1 = 350 HB
HB2 = 285 HB
Qv = 10
ψs = 7.5 deg
φn = 25 deg
L = 219000 hours
q = 1
Pnd = 25.4 mm
x1 = 0.2418
x2 = --0.2418
dO1 = 703.565 mm
dO2 = 6033.402 mm
Modified leads
Bearing supported mill
Pinion steel material grade M2
Gear spheroidal graphitic material grade M2
a = 3317.6845 mm
ZE = 184 (N/mm2)0.5
E.4.1 Calculations
= 9.36
u=
Ng
Np
= 640.4796 mm
dw1=
2 C
mG+ 1
= 25.6192 mm
mt=
mn
cos π180 βs
= 1.2
mB=
tR
ht
= 1
KBm= − 1.788 mB+ 2.7636 if mB< 1.0
1.0 otherwise
ZI = 0.2646
YJ1 = 0.6362
YJ2 = 0.6513
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
52 © AGMA 2006 ---- All rights reserved
= 0.5875
Bmill=
12−Qv− (Qv−6)210 
0.667
4
= 73.1011
Cmill= 50+ 56 1− Bmill
= 5.1051 m∕s
vt=
π ω1 dw1
60000
= 1.2367
Kvm=Cmill+ 196.85 vtCmill 
Bmill
HB1
HB2
= 1.2281
0.00698 otherwise
A= 0 if
HB1
HB2
< 1.2
0.00898 HB1
HB2
− 0.00829 if 1.2≤ HB1
HB2
≤ 1.7
= 0.0027
= 1.0229
ZW= 1+ A (u− 1)
KHmc = 0.95
KHpm = 1.0
KHe = 0.8
b
10 dw1
− 0.1109+ 0.000815 b− 0.000000353 b2 otherwise
KHpf=  b10 dw1− 0.0375+ 0.000492 b if b≤ 432
= 0.423
A = 1.27× 10--1
B = 0.622× 10--3
C = --1.69× 10--7
= 0.5019
KHma= A+ B b+ C b
2
= 1.7837
KHβ= 1.0+ KHmc KHpf KHpm+ KHma KHe
KH= KHβ
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
53© AGMA 2006 ---- All rights reserved
= 1078.45 N∕mm2
σHP1= 2.407 HB1+ 236
= 359.05 N∕mm2
σFP1= 0.703 HB1+ 113
= 866 N∕mm2
σHP2= 2.26 HB2+ 222.1
= 241.47 N∕mm2
σHP2= 0.542 HB2+ 87.1
= 2.0183× 109
nL= 60 L w1
2.2496 n−0.0503L  otherwise
ZNp= 1.2942 if nL< 10
4
= 0.7657
2.466 n−0.056L  if 104≤ nL≤ 107
1.6831 n−0.0323L  otherwise
YNp= 1.5995 if nL< 10
3
= 0.8425
2.3194 n−0.0538L  if 103≤ nL≤ 3× 106
= 2.1563× 107
nL= 60 Lω1u  q
2.2496 n−0.0503L  otherwise
ZNg= 1.2942 if nL< 10
4
= 0.8569
2.466 n−0.056L  if 104≤ nL≤ 107
1.6831 n−0.0323L  otherwise
YNg= 1.5995 if nL< 10
3
= 0.9056
2.3194 n−0.0538L  if 103≤ nL≤ 3× 106
= 6058
Pazm1=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP1 ZN1
ZE
2
= 5121
Pazm2=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP2 ZN2 ZW
ZE
2
= 8750
Paym1=
π ω1 dw1
6× 107 Kvm
b mt YJ1 σFP1 YN1
KH KBm
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
54 © AGMA 2006 ---- All rights reserved
= 6478
Paym2=
π ω1 dw1
6× 107 Kvm
b mt YJ2 σFP2 YN2
KH KBm
= 2591 kw
Pa= minPazm1CSF , Pazm2CSF ,
Paym1
KSF
,
Paym2
KSF

E.5 Application SAG mill dual pinion
P = 5220 kw
CSF = 1.750
KSF = 2.50
ω1 = 180 rpm
b = 838 mm
Np = 19
Ng = 284
tR = 85.73 mm
ht = 76.73 mm
HR1 = 55 HRC
HB2 = 325 HB
Qv = 10
ψs = 8.100 deg
φn = 25 deg
L = 219000 hours
q = 2
mn = 33.867 mm
x1 = 0.1
x2 = --0.1
dO1 = 724.510 mm
dO2 = 9775.93 mm
Modified leads
Bearing supported mill
Steel material grade M2
a = 5182.502 mm
ZE = 9775.93 (N/mm2)0.5
E.5.1 Calculations
= 14.9474
u=
Ng
Np
= 649.951 mm
dw1=
2 a
u+ 1
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
55© AGMA 2006 ---- All rights reserved
= 34.2083 mm
mt= mn cos π180 βs
= 1.1172
mB=
tR
ht
= 1
KBm= − 1.788 mB+ 2.7636 if mB< 1.0
1.0 otherwise
ZI = 0.2742
YJ1 = 0.6132
YJ2 = 0.6863
= 0.5875
Bmill=
12−Qv− (Qv−6)210 
0.667
4
= 73.1011
Cmill= 50+ 56 1− Bmill
= 6.1256 m∕s
vt=
π ω1 dw1
60000
= 1.2565
Kvm=Cmill+ 196.85 vtCmill 
Bmill
= 565.1858
HB1= 6.96608× 10
−2+⎪
⎧
⎩
1.0
− 9.68063× 10−5− 1.62552× 10−9 H3
R1
+ 0.117524HR1
⎪
⎫
⎭
HB1
HB2
= 1.7390
0.00967 otherwise
A= 0 if
HB1
HB2
< 1.2
0.00898 HB1
HB2
− 0.00829 if 1.2≤ HB1
HB2
≤ 2.0
= 0.0073
= 1.1021
ZW= 1+ A (u− 1)
KHmc = 0.95
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
56 © AGMA 2006 ---- All rights reserved
KHpm = 1.0
KHe = 0.8
b
10 dw1
− 0.1109+ 0.0207 b− 0.000228 b2 otherwise
KHpf=  b10 dw1− 0.0375+ 0.0125 b if b≤ 17
= 0.4531
A = 1.27× 10--1
B = 0.622× 10--3
C = --1.69× 10--7
= 0.5296
KHma= A+ B b+ C b
2
= 1.8329
KHβ= 1.0+ KHmc KHpf KHpm+ KHma KHe
KH= KHβ
σHP1= 1450 N∕mm
2
σFP1= 425 N∕mm
2
= 1018.275 N∕mm2
σHP2= 2.407 HB2+ 236
= 341.475 N∕mm2
σFP2= 0.703 HB2+ 113
= 2.3652× 109
nL= 60 L ω1
1.8902 n−0.0395L  otherwise
ZN1= 1.2942 if nL< 10
4
= 0.8058
2.466 n−0.056L  if 104≤ nL≤ 107
1.6831 n−0.0323L  otherwise
YN1= 1.5995 if nL< 10
3
= 0.8382
2.3194 n−0.0538L  if 103≤ nL≤ 3× 106
= 3.1647× 108
nL= 60 Lω1u  q
2.2496 n−0.0503L  otherwise
ZN2= 1.2942 if nL< 10
4
= 0.8405
2.466 n−0.056L  if 104≤ nL≤ 107
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
57© AGMA 2006 ---- All rights reserved
1.6831 n−0.0323L  otherwise
YN2= 1.5995 if nL< 10
3
= 0.8944
2.3194 n−0.0538L  if 103≤ nL≤ 3× 106
= 15022
Pazm1=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP1 ZN1
ZE
2
= 9791
Pazm2=
π ω1 b
6× 107
ZI
Kvm KH
dw1 σHP2 ZN2 ZW
ZE
2
= 16655
Paym1=
π ω1 dw1
6× 107 Kvm
b mt YJ1 σFP1 YN1
KH KBm
= 15982
Paym2=
π ω1 dw1
6× 107 Kvm
b mt YJ2 σFP2 YN2
KH KBm
= 5595 kw
Pa= minPazm1CSF , Pazm2CSF ,
Paym1
KSF
,
Paym2
KSF

Copyright American Gear Manufacturers Association 
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
58 © AGMA 2006 ---- All rights reserved
Annex F
(informative)
Material mechanical properties
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
F.1 Purpose
The purpose of this annex is to provide minimum
mechanical material property values. These values
are intended to aid the preparation of specifications
by purchasers of gearing, when material property
tests, in addition to the measured hardness value,
are desired.
Table F.1 – Alloy steel
Hardness
Tensile
strength Yield strengthHardness,
HB
strength,
N/mm2 (min)
Yield strength,
N/mm2 (min)
160 496 288
180 558 351
200 621 414
210 653 445
225 700 493
245 762 555
255 794 587
265 825 618
285 888 681
300 935 728
310 967 759
325 1014 807
335 1045 838
350 1092 885
365 1139 932
375 1171 964
NOTES:
1. The following formulas apply to the values within the
table and can be used to determineminimum tensile and
yield values for hardness values not listed.
Tensile (N/mm2) = 3.14 x (HB) – 6.9
Yield (N/mm2) = 3.14 x (HB) – 214
2. Values apply only to alloy steel and are independent
of heat treatment.
3. Values are informational only. The purchaser and
seller can specify other values by contractual agree-
ment.
F.2 Description
Development of mechanical property data requires
numerous test samples and statistical analysis to
determine appropriate values. Values presented
within this annex are based on a review of published
data and represent the minimum published values,
see tables F.1 and F.2. Since the values listed within
this annex are minimums, results of any individual
test should meet or exceed the given values
If any individual test results are less than the values
listed, the cause should be investigated. Issues to
investigate include:
-- test specimen hardness;
-- test specimen preparation errors (e.g.,
machining marks);
-- material flaws;
-- testing errors.
In the event of a non--conforming test, additional
tests should be performed. Should additional tests
fail to reach theminimum values given, the purchas-
er and seller should mutually agree to the corrective
action necessary to achieve a passing result.
Table F.2 -- Spheroidal graphitic iron
Hardness,
HB
Tensile
strength,
N/mm2 (min)
Yield strength,
N/mm2 (min)
200 486 274
240 585 343
280 683 411
310 757 463
NOTES:
1. The following formulas apply to the values within the
table and can be used to determine minimum tensile and
yield values for hardness values within the range of the
table values.
Tensile (N/mm2) = 2.78 (HB) -- 8.25
Yield (N/mm2) = 1.71 (HB) – 67.6
2. Values only apply to spheroidal graphitic iron.
3. Values are for informational purposes only. The
purchaser and manufacturer can specify other values by
contractual agreement.
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
59© AGMA 2006 ---- All rights reserved
Annex G
(informative)
Operation and maintenance
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
G.1 Purpose
This annex provides a brief discussion of site
considerations, operation, and maintenance of gear
sets for cylindrical grinding mills, kilns, coolers, and
dryers.
G.2 Startup
The startup ofthe equipment should begin with
verification and baseline measurements of radial
and axial runouts, root clearance, backlash, align-
ment, contact pattern check, and vibrationmeasure-
ments. In this manner an equipment signature will
be established. Distribution of lubricant should also
be verified before starting the equipment. Consult
the equipment manufacturer for a run--in procedure.
G.3 Operation
For roller supported equipment it is extremely
important to consider the gear and pinion alignment
beforemakingsupport roller adjustments at thedrive
pier. After a roller adjustment, gear and pinion
alignment must be checked.
When adjusting drive components (i.e., clutches,
motors, couplings, etc.), be aware of the effects on
the gear and pinion alignment.
If changes in power draw or speed occur, tooth
contact conditions should be examined. Increases
in installed power, or changes in operating speed
should always be reviewed by the gear designer.
When tooth flank wear is such that it requires
reversing the pinion, best practice is to reverse the
gear as well. In this manner a new pinion flank is in
mesh with a new gear flank. When both gear tooth
flanks are worn, the gear could be re--machined and
put back into service with a new pinion. Worn tooth
flanks are not compatible with new tooth flanks. If a
worn tooth flank is meshed with a new tooth flank,
destructive damage may occur, including:
-- reduced pinion and gear life;
-- increased vibration and noise;
-- tooth surface pitting;
-- tooth breakage.
Whenaligningworn components caremust be taken
such that axial wear steps are not in the activemesh,
see A.3.1. Additionally, root clearance should be
sufficient such that axial and radial wear steps are
not in mesh. If wear steps are brought into mesh,
significant vibration or tooth breakagemay result. In
all cases interference (loss of backlash) must be
avoided.
On grinding mills, alignment of the pinion should be
monitored by way of infrared temperature profiles.
When performing temperature measurements, uti-
lize thesamepersonnel for consistency. Beawareof
false temperature readings due to damaged teeth,
seals rubbing, and excessive equipment shell tem-
peratures. On other equipment, such as kilns and
dryers, the contact pattern should be monitored.
For flange mounted gears, always adhere to the
recommended mounting flange torque require-
ments. Do not exceed the values recommended by
the manufacturer. Avoid interference or tight fitting
flange bolts. Gear adjustment jack bolts should be
removed or loosened and kept away from the
mounting flange when alignment is completed.
G.4 Shutdown inspections and maintenance
Shutdown inspections should include cleaning the
entire gear, pinion(s), and inside of the gear guard.
This allows an accurate visual inspection of the
components and removes contaminants which can
prematurely wear the gear and pinion. Refer to table
G.1 for suggested inspections.
When washing down the equipment, never direct
water at the gear guard seals.
G.5 Lubrication
Most gear failures are in some way related to
contamination and improper lubrication. Regular
inspections should confirm that the gear and pinion
are adequately lubricated. Other important tasks
include keeping the lubricant free of foreignmaterial,
and contaminants and water out of the gear guard.
Gear guard dust seals should also be inspected
regularly to ensure that theyare functioningproperly.
Copyright American Gear Manufacturers Association 
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
60 © AGMA 2006 ---- All rights reserved
If using a bath or reservoir of oil, check the lubricant
for abrasive dust, water and foreign particles, and
replace if it is contaminated. It is important to note
that all formulas in this standard are based on clean
operating conditions. Always consult with the gear
designer when changing lubricants or lubricant
suppliers. Important issues include: point of applica-
tion (prior to mesh or after mesh, and whether to
apply the lubricant on thegear or thepinion), quantity
of lubricant, and the frequency of its application.
See Annex D for additional lubrication discussions.
Table G.1 -- Inspections
Inspection Frequency Notes
Lube analysis Monthly
Vibration analysis Monthly
Infrared alignment Weekly Monitor and analyze trends before adjusting alignment
Visual inspection Annually Gear, pinion, mounting hardware, joint blocks. Any signs
of damage may require further inspections i.e., magnetic
particle
Gear joint tightness
inspection
Annually Check joint tightness with feeler gauges and joint align-
ment
Pictures Annually for cleaned
gearing at shut down
Document condition of gear and pinion, record teeth
numbers
Monthly with gearing
in operation
Document condition of gear and pinion
Contact pattern Annually
Root clearance Annually Roller supported equipment
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
61© AGMA 2006 ---- All rights reserved
Annex H
(informative)
Ausferritic ductile iron (ADI)
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
H.1 Introduction
Spheroidal graphitc (SG) iron had been successfully
used in the gear industry prior to 1970, when
research work started to define the optimum values
of SG iron for gear materials. The result of this work
was a new material, with a new microstructure,
which is now called ausferritic ductile iron (ADI). ADI
is an alloyed SG iron that is heat treated before or
after machining, depending on properties and accu-
racy requirements.
The heat treatment process is called austempering.
The first stage of the process is austenitizing, which
is carried out in a shielded atmosphere in order to
avoid decarburizing of the surface. The second
stage is rapid quenching to the isothermal tempera-
ture where the transformation of austenite to ausfer-
ritic microstructure occurs. There are possibilities to
get different grades of ADI depending on the
isothermal temperature. The heat treatment pro-
cess needs enough alloying elements to avoid
pearlitic transformation during the rapid quenching.
With increasing section thickness, more alloying
elements are needed, and this will also have an
effect on the heat treatment parameters. In order to
get the optimum properties, it is important to use the
right combinations of alloying, austenitizing temper-
atureand time, aswell as austempering temperature
and time.
The matrix of ADI microstructure is a mixture of
austenite and ferrite, giving high strength, ductility
and wear properties. The austenite must be
thermally stable to get the best possible ductility
values. Austenite will stay stable in normal working
temperatures, down to --50° C. Unstable austenite
transforms to martensite, which is the main reason
for brittleness and detrimental effects in machining
operations after heat treatment. When compared
with other known microstructures of ductile irons,
ADI has a strain hardening effect, and this increases
the fatigue and wear properties compared to steels
or other SG iron grades.
H.2 Allowable stress numbers σHP and σFP
ADI was initially applied in the small size gear
industry. While the contact fatigue strength of
pearlitic or quenched and tempered SG iron has
values comparable to quenchedand tempered steel
of the same hardness, the ausferritic ductile iron has
about 20--25% higher values than other SG irons
withequal hardness. Becauseof thegoodductility of
ADI, there is also a possibility to use grades with
higher hardness and tensile strength than that
possible with quenched and tempered SG iron. The
allowed contact strength properties will increase
together with tensile strength. The bending fatigue
strength also depends on the hardness of the
material. The optimum range of the gear properties
is achieved when the tensile strength is 1100 -- 1200
N/mm2. By shot peening, or other cold working
methods, the bending fatigue can be further in-
creased.
ADI requires different machining technology and
tools when compared with steel. While strength
increases, machining becomes more difficult. Typi-
cally pre--machining isperformedbeforeaustemper-
ing, and finishing is performed after heat treatment.
Allowable stress numbers for gear materials vary
with items such as material composition, cleanli-
ness, residual stress, microstructure, quality, heat
treatment, and processing practices.
Allowable stress numbers in this annex are deter-
mined or estimated from laboratory tests and
accumulated field experiences, see figures H.1 and
H.2. They are based on unity overload factor, 10
million stress cycles and unidirectional loading.
Allowable stress numbers are designated as σHP
and σFP, for pitting resistance and bending strength,
respectively. For service life other than 10 million
cycles, allowablestressnumbersareadjustedby the
use of stress cycle factors, see clause15 and figures
H.3 and H.4.
Allowable stress numbers for ADI gears are estab-
lished by specific quality control requirements for
eachmaterial grade. All requirements for the quality
grade as listed in table H.1 must be met in order to
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
62 © AGMA 2006 ---- All rights reserved
use the stress values for that grade. This shall be
accomplishedby specifically certifying each require-
ment when specified. It is not the intent of this annex
that all requirements for quality grades be certified,
but that practicesandproceduresareestablished for
their compliance on a production basis. Intermedi-
ate values shall not be used since the effect of
deviations from the quality standards cannot be
evaluated easily. Allowable stress numbers are
shown in figures H.1 and H.2.
125000
150000
175000
200000
275 300 325 350 375
Brinell hardness, HB
A
llo
w
ab
le
co
nt
ac
ts
tr
es
s
nu
m
be
r,
σ H
P
(N
/m
m
2 )
Grade M2
σHP = 2.68 HB + 264
Grade M1
σHP = 2.55 HB + 251
860
1030
1205
1380
Figure H.1 -- Allowable contact stress number for ADI gears, σHP
138
206
276
345
275 300 325 350 375
Brinell hardness, HB
A
llo
w
ab
le
be
nd
in
g
st
re
ss
nu
m
be
r,
σ F
P
(N
/m
m
2 )
Grade M2
σFP = --0.8 HB + 264
Grade M1
σFP = --0.762 HB + 503
Figure H.2 -- Allowable bending stress number for ADI gears, σFP
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
63© AGMA 2006 ---- All rights reserved
0.5
0.6
0.7
0.8
0.9
1.0
2.0
3.0
4.0
5.0
102 103 104 105 106 107 108 109 1010
Number of load cycles, nL
ZN = 3.8221 nL--0.0756
ZN = 2.6182 nL--0.0543
S
tr
es
s
cy
cl
e
fa
ct
or
,Z
N
Figure H.3 -- ADI pitting resistance stress cycle factor, ZN
0.5
0.6
0.7
0.8
0.9
1.0
2.0
3.0
4.0
5.0
102 103 104 105 106 107 108 109 1010
Number of load cycles, nL
YN = 10.9749 nL--0.1606
YN = 1.0780 nL--0.005
S
tr
es
s
cy
cl
e
fa
ct
or
,Y
N
Figure H.4 -- ADI bending strength stress cycle factor, YN
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
64 © AGMA 2006 ---- All rights reserved
Table H.1 -- Metallurgical characteristics for ausferritic cast iron gears
Item Characteristic1) Grade M1 Grade M2
1 Material chemistry Certification not
required.
Test report per ASTM E351.
2 Microstructure Certification not
required.
Test per ASTM A247 or ISO 945. Graphite form
min 85% type V and VI. Fully ausferritic matrix in
cross--section.
3 Material form ADI 1050/700/7. Mechanical properties ASTM A897 (ISO 17804: JS
1050--6).
4 Heat treatment Ausferritizing: Austenizing followedbyaustempering treatment (isothermal
quenching).
5 Hardness testing 2) Certification not
required.
Hardness testing is required on semi--finished
gear blanks 3 mmmaximum stock and using only
Brinell or Equotip hardness testers calibrated for
ADI. The minimum measured hardness value
shall meet the specified design requirement. A
maximum40HB range inmeasuredhardness val-
ues is recommended. A minimum of twelve mea-
surements shall be taken, four equally spaced on
each rimedgeat the root diameter. If individual ris-
ers are used for casting, the hardness measure-
ment on the cope side shall be performed in the
riser area. Four equally spaced measurements
shall also be taken around the circumference on
the outside diameter at mid--face.
6 Mechanical testing 3) Mechanical properties are to be obtained in accordance with ASTM E8.
Properties for each gear segment are to be confirmed by testing of speci-
mens representative of the rim thickness. Test specimens shall undergo
the equivalent heat treatment process with the gear segments they repres-
ent. Test piece dimensionsmust be in accordancewith the component wall
thickness it represents.
7 Stress relief Annealing after casting prior to ausferritizing.
8 Weld repair Not allowed.
9 Ultrasonic inspection
4), 5), 6)
Certification not
required.
Ultrasonic Testing per ASTM A609 in two perpen-
dicular directions to the following limits. All test
surfaces to be machined to a maximum of 6.2 mm
surface finish.
-- Flat bottom hole technique
-- Zone 1 – Level 1: 3mm flat bottomhole straight
beam
-- Zone 2 – Level 2: 6mm flat bottomhole straight
beam
For both zones paragraphs 10.2.1, 10.2.2 and
10.2.3 of ASTM A609 shall apply. Also, cracks,
tears, cold shuts, unfused chaplets or a complete
loss of back reflection not attributable to the geo-
metric configuration (defined as less than 5% of
full screen height), are not acceptable.
Calibration reference blocks shall be ADI--materi-
al and the DGS technique is also acceptable.
10 Nodularity Minimum sound velocity of 5400m/sec after ausferritizing11) at four equally
spaced points on the rim of each gear segment is required.
(continued)
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
65© AGMA 2006 ---- All rights reserved
Table H.1 (concluded)
Item Characteristic1) Grade M1 Grade M2
11 Magnetic particle in-
spection of gear blank
(Zone 2) 4), 5), 6), 7), 8)
Certification not
required.
Magnetic particle inspection is performed accord-
ing to ASTME1444 whenagreed between suppli-
er and purchaser. Anyindication greater than 6
mm shall be reported. No cracks, seams, laps, or
tears are allowed.
12 Magnetic particle in-
spection of finished
gear teeth or roots
(Zone 1) 4), 5), 6)
Magnetic particle inspection is performed according to ASTM E1444 when
agreedbetweensupplier andpurchaser. The technique shoulduse the true
continuous method, wet fluorescent or wet visible, with direct or indirect
magnetization, in two directions.
Acceptance criteria per tooth flank:
-- Sum of the lengths must not exceed 10% of face width.
-- Any indication greater than 6 mm shall be reported.
-- Any single linear9) indication located below the operating pitch diameter
which lies parallel to the teeth shall be reported.
-- No cracks, seams, laps, or tears are allowed.
13 100%visual inspection
of the finished gearing
7), 8)
Inspection to following limits: No linear indications, cracks, seams, laps, or
tears are allowed.
14 Shot peening 10) Shot peeningmay be used to increase surface residual compressive stres-
ses. See SAE/AMS--S--13165.
NOTES:
1) Metallurgical requirements assume homogenous composition. In practice, microsegregation, graphite deformity and
carbide formation may occur. These variations in microstructure and resultingmechanical properties must be assessed.
2) See ASTM A370, ASTM E140 or ISO 6336--5 annex C for hardness conversion tables.
3) Mechanical properties are defined to mean tensile, yield, elongation and reduction of area.
4) Zone 1 is defined as the volumewithin the gear blank outside diameter extending to aminimumdepth of 25mmbelow
the roots of finished gear teeth including the segment joint flanges from the outside diameter to 25 mm below the roots
of the finished gear teeth. Zone 2 is defined as the gear rim and segment joint flange volumes not included in Zone 1
and any other parts of the gear structure that the purchaser and seller consider necessary to examine.
5) Dross is not acceptable unless there is an engineering evaluation performed.
6) In--process ultrasonic and/or magnetic particle inspection of gearing blanks is recommended for large diameter parts
to detect flaws before including the expense of further machining.
7) Removal of defects that exceed the stated limits is acceptable, provided integrity of gear is not compromised.
8) Defects in non--functional areas require engineering disposition.
9) Linear is defined as any indication with length greater than 3 times width.
10) It is recommended that ANSI/AGMA 2004--B89 be reviewed to determine if the benefits of root surface residual com-
pressive stress achieved by shot peening may be beneficial to the particular application. Work hardening is significant
for ADI materials. Machining may cause similar effects to shot peening. Shot peening should be considered for roots
only, since the flanks will obtain some effect just from contact operation.
11) There is typical reduction of 300 ft/sec in sound velocity when measured after ausferritizing.
Copyright American Gear Manufacturers Association 
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
66 © AGMA 2006 ---- All rights reserved
Table H.2 -- Practical industrial values for ADI as gear material
Values are minimum for section thickness up to 50 mm. Heavier sections will have lower values and
properties must be agreed between purchaser and manufacturer.
Criteria Minimum values
Tensile strength, Rm
0.2% proof strength, Rp0.2
Elongation, A5
1000 N/mm2
800 N/mm2
5%
Compression strength, σdb
0.2% proof stress
1600 N/mm2
770 N/mm2
Shear strength, σaB 900 N/mm2
Torsional strength, τtB
0.2% proof stress
900 N/mm2
490 N/mm2
Impact energy Charpy unnotched
(25 ±5°C)
80 J
Fracture toughness, KIC 1840 N mm(0.5)/mm2
Typical values
Brinell hardness 300--360 HB
Modulus of elasticity, E 1.683× 105 N/mm2
Poisson’s ratio, ν 0.27
Shear modulus 6.414× 104 N/mm2
Density, ρ 7100 kg/m3
Copyright American Gear Manufacturers Association 
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--```,,,````````````````,,`,,`,-`-`,,`,,`,`,,`---
ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
67© AGMA 2006 ---- All rights reserved
Annex I
(informative)
Service factors
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
I.1 Purpose
This annex discusses the various terms used to
specify capacity in excess of input power require-
ments, factors of safety, overload factors, service
factors and other considerations for geared sys-
tems.
I.2 Minimum service factors
The table of service factors shown in this annex has
been developed from the experience of manufactur-
ers and users of gears for cylindrical grinding mills,
kilns, coolers and dryers with electric motor prime
movers. The user and the gearmanufacturer should
agree upon service factors. For applications not
listed in table I.1, service factors should be defined
by contractual agreement. Note that some applica-
tions use calculated demand (brake) power instead
ofmotor nameplatepower toestablishservice factor.
Table I.1 -- Minimum service factors
(for a duty cycles of 24 hours per day)
Application CSF KSF
Kilns 1.751), 3)
Coolers 1.001), 2)
1 501), 3)
Dryers
1.501), 3)
Ball mills
4)Autogenous/SAG
mills
1.50 or 1.754) 2.50
Rod mills 1.65 or 1.754) 2.60
NOTES:
1) When the gear speed is greater than or equal to 1.5
rpm, multiply the service factors listed in the above table
by [0.07*ω2 +0.90] where ω2 is the speed of the gear in
rpm.
2) Maximum value is 1.40.
3) Maximum value is 2.25.
4) For high power grindingmills ( > 3350 kW), single cir-
cuit processes, or other critical applications, use
CSF = 1.75.
Unless otherwise specified by contractual agree-
ment, the connectedmotor nameplate power includ-
ing motor service factor shall be used to determine
service factors. When not provided by the
purchaser, motor service factor equal to 1.0 shall be
used.
Dual drive applications, where two pinions drive one
gear, should use the prime mover power on each
trainwhen computing a service factor of the gear set.
Note that adjustment to the number of load cycles in
the calculation of stress cycle factors, ZN and YN, on
the gear is required.
Combination Ball -- RodMills use the service factors
specified for rod mills.
I.3 Other considerations
I.3.1 Non--gear components
Every component of a gearmust allow for the proper
transmission of power, considering both internal and
external loading. These components, such as
housing supports, shafting, bearings, and fasteners
must be designed andmanufactured to maintain the
gears in proper position as well as transmit the
required power.
I.3.2 Prime mover selection
The type of primemover of a gear systemcan havea
significant impact on the service factor selected and
the overall performance of the gear set. Required
starting loads, the method of connection between
the prime mover, the gear set, and the driven
equipment should be reviewed. Motors with high
starting torque capacity (> 250% of motor power)
andanapplication that has frequent start/stop cycles
may require that the gear set be designed to address
these peak loads. A dual drive application is where
two motors drive two gear trains that mesh with a
commongear on thedrivenequipment. It is critical to
balance the load of each of these trains so that one
side is not excessively carrying the load. See annex
B for additional discussion of this topic.
Copyright American Gear Manufacturers AssociationProvided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
68 © AGMA 2006 ---- All rights reserved
I.3.3 Driven equipment
Service factors are based on the experience of the
application. Unbalanced loads, starting require-
ments, changes of alignment during operation, and
long term reliability all play a role in determining the
service factor.
It is critical to ensure that during the design process,
an understanding of the type, magnitude, direction,
and duration of all loads that the gear set will
experience are considered. In dual drive applica-
tions, the inching ormaintenance drive is required to
produce the same output torque as in main drive
operation. Since this load is transmitted through one
side of the gear train, analysis is required to ensure
that all components are not stressed beyond design
limits.
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
69© AGMA 2006 ---- All rights reserved
Annex J
(informative)
Method for determination of dynamic factor with AGMA 2000--A88
[The foreword, footnotes and annexes, if any, are provided for informational purposes only and should not be
construed as a part of ANSI/AGMA 6114--A06, Gear Power Rating for Cylindrical Shell and Trunnion Supported
Equipment (Metric Edition).]
J.1 Purpose
Thestandardmethodof thedeterminationof dynam-
ic factor is given in clause 8, with the use of
ANSI/AGMA 2015--1--A01. This annex is to provide
an alternative method using the previous standard
AGMA 2000--A88. A specific geometry, procedure,
and operating conditions should result in a compara-
ble dynamic factor using this annex or clause 8.
J.2 Approximate dynamic factor, Kvm
Figure J.1 shows dynamic factors that should be
used. The curves of figure J.1 and the equations
given are based on empirical data, and do not
account for resonance. Due to the approximate
nature of the empirical curves and the lack of
measured tolerance values at the design stage, the
dynamic factor curve should be selected based on
experience with the manufacturing methods and
operating considerations of the design.
Choice of curves Qv = 6 through Qv = 10 should be
based on transmission error. When transmission
error is not available, it is reasonable to refer to the
pitch accuracy, and to some extent profile accuracy,
as a representative value to determine the dynamic
factor. Qv is related to the transmission accuracy
grade number. Due to the approximationmentioned
above, slight variation from the selected Qv value is
not considered significant to the gear set rating.
1
1.1
1.2
1.3
1.4
1.5
1.6
0 2.5 5.0 7.5 10.0
Pitchline velocity, vt, m/s
D
yn
am
ic
fa
ct
or
,K
vm
Qv = 10
Qv = 7
Qv = 8
Qv = 9
Qv = 6
Figure J.1 -- Dynamic factor, Kvm
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06 AMERICAN NATIONAL STANDARD
70 © AGMA 2006 ---- All rights reserved
J.3 Curves labeled Qv = 6 through Qv = 10
The empirical curves of figure J.1 are generated by
the following equations for integer values ofQv, such
that 6≤ Qv≤ 10. Qv is related to the transmission
accuracy grade number.
Qv can be estimated as the appropriate quality
number for the expected pitch and profile variations
in accordance with AGMA 2000--A88.
The lowest value for Qv based on pitch and profile
should be used for calculating Kvm.
Kvm= Cmill
Cmill+ 196.85 vt
−Bmill (J.1)
where
Cmill= 50+ 56 1− Bmill (J.2)
Bmill=
12−Qv− (Qv−6)210 
0.667
4
(J.3)
where
Bmill is exponential accuracy adjustment to Kvm
for open gearing;
Cmill is linear adjustment toKvm for open gearing.
Values less than Qv = 6 are not allowed. When Qv >
10, use Qv = 10.
Theminimum value ofKvm when using this standard
is 1.02.
Copyright American Gear Manufacturers Association 
Provided by IHS under license with AGMA Licensee=IHS Employees/1111111001, User=Wing, Bernie
Not for Resale, 04/18/2007 03:09:35 MDTNo reproduction or networking permitted without license from IHS
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ANSI/AGMA 6114--A06AMERICAN NATIONAL STANDARD
71© AGMA 2006 ---- All rights reserved
Bibliography
The following documents are either referenced in the text of ANSI/AGMA 6114--A06, Gear Power Rating for
Cylindrical Shell and Trunnion Supported Equipment (Metric Edition) or indicated for additional information.
[1] Dolan T.J. and Broghamer E.L., A Photoelastic
Study of the Stresses in Gear Tooth Fillets, Univer-
sity of Illinois, Engineering Experiment Station,
Bulletin No. 335, 1942.
[2] Drago, R. J., AGMA P229.24, An Improvement
in theConventional Analysis ofGear ToothBending
Fatigue Strength, October 1982.
[3] Dowson, D., Toyoda, S., ”A Central Film
Thickness Formula for Elastohydrodynamic Line
Contacts,” 5th Leeds--Lyon Sumposium Proceed-
ings, paper 11, VII, 1978, pp. 60--65.
[4] Wellauer, E., and Holloway, G., ”Application of
EHD Oil Film Theory to Industrial Gear Drives,”
Trans. ASME, J. Eng. Ind., Vol. 98, Series B, No. 2,
May 1976, pp. 626--634.
AGMA 925--A03, Effect of Lubrication on Gear
Surface Distress.
AGMA 927--A01, Load Distribution Factors – Ana-
lytical Methods for Cylindrical Gears.
ANSI/AGMA 2101--D04, Fundamental Rating Fac-
tors and Calculation Methods for Involute Spur and
Helical Gear Teeth
ANSI/AGMA1010--E95,AppearanceofGear Teeth
-- Terminology of Wear and Failure
ANSI/AGMA 9005--E02, Industrial Gear Lubrica-
tion.
AGMA 2000--A88, Gear Classification and Inspec-
tion Handbook -- Tolerances and Measuring Meth-
ods for Unassembled Spur and Helical Gears
(Including Metric Equivalents)
ASTM A897, Standard Specification For Austemp-
ered Ductile Iron Castings
ISO 17804, Founding -- Ausferritic Spheroidal
Graphite Cast Irons -- Classification
JIS G5503:1995, Austempered Spheroidal Graph-
ite Iron Castings.
Moyer, C., and Bahney, L., “Modifying the Lambda
Ratio to Functional Line Contacts”, STLE Preprint
No. 89--TC--5A--1, pp. 1--7.
SAEJ2477:2004,AutomotiveAustemperedDuctile
(Nodular) Iron Castings (ADI).
Copyright American Gear Manufacturers Association 
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PUBLISHED BY
AMERICAN GEAR MANUFACTURERS ASSOCIATION
500 MONTGOMERY STREET, SUITE 350
ALEXANDRIA, VIRGINIA 22314
Copyright American Gear Manufacturers Association 
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