Artigo_M

Prévia do material em texto

Journal of Manufacturing Processes 103 (2023) 156–167
Available online 26 August 2023
1526-6125/© 2023 The Author(s). Published by Elsevier Ltd on behalf of The Society of Manufacturing Engineers. This is an open access article under the CC BY
license (http://creativecommons.org/licenses/by/4.0/).
Comprehensive analysis of tool wear, surface roughness and chip 
morphology in sustainable turning of Inconel-601 alloy 
Mehmet Erdi Korkmaz a, Munish Kumar Gupta b,c,*, Mustafa Günay a, Mehmet Boy d, 
Nafiz Yaşar e, Recep Demirsöz a, K. Nimel Sworna Ross f, Yasir Abbas a 
a Department of Mechanical Engineering, Karabük University, Karabük, Turkey 
b Faculty of Mechanical Engineering, Opole University of Technology, 76 Proszkowska St., 45-758 Opole, Poland 
c Department of mechanical engineering, Graphic Era (Deemed to be university), Dehradun, India 
d TOBB Vocational High School, Karabük University, Karabük, Turkey 
e Department of Mechanical Engineering, Dumlupınar University, Turkey 
f Department of Mechanical and Industrial Engineering Technology, University of Johannesburg, Johannesburg, South Africa 
A R T I C L E I N F O 
Keywords: 
Tool wear 
Surface roughness 
Cooling 
Sustainable manufacturing 
Tribology 
A B S T R A C T 
The objective of this research was to explore the impact of various cooling conditions on machinability, as 
potential alternatives to traditional cooling methods. To achieve this aim, a series of experiments were per-
formed, where dry machining, minimum quantity lubrication (MQL), nanofluids, cryogenic (cryo) cooling, and 
hybrid cooling (cryo+nano MQL) methods were tested. Under distinct nanofluids conditions hBN(0.2 %) +
graphene(0.2 %) performed well and overall cryo+nano MQL produced better result in terms of tool wear, 
microhardness, surface and chip morphology. The results demonstrated that the cooling effect of the Cryo-MQL 
regime, which maintains the cutting temperature at a tolerable level and preserves the lubricant performance of 
the MQL, is the cause of the lowest Vb value of 90 μm. 
1. Introduction 
In machining, the relative motion and cutting force between the 
insert and workpiece are necessary for chip formation. Friction, which 
occurs due to the action and force effect, causes an increase in temper-
ature. Heat is generated by internal frictions in the primary deformation 
region, internal and external frictions in the secondary deformation re-
gion (tool-chip interface), and friction and deformation between the 
machined surface under the tool cutting edge and flank side [1]. This 
heat, and therefore temperature, causes a decrease in hardness, in-
creases tool wear, shortens life, and may cause plastic deformation of the 
tool [2]. In machining, cutting tools complete their life by wear down, 
undergoing plastic deformation or breaking. As the tool reaches the end 
of its life, deviations occur in the machined part dimensions and the 
surface quality decreases [3]. At this stage, the tool must be replaced and 
for that purpose, different methods are used in factories and laboratories 
to predict tool life. There are many parameters such as workpiece ma-
terial type, tool type, cutting speed, feed rate, depth of cut, heat 
generated, coolant and machine construction affecting the surface 
roughness in machining. With the change of one of these factors, the 
surface roughness also changes [4]. In general, flank wear (tool surface 
in contact with the machined surface) is used as a criterion because it is 
the type of wear that usually determines surface roughness and accu-
racy. Depending on time, first the flank wear is dominant, but after a 
long time, crater wear takes the lead and becomes the life criterion. 
Factors such as high stresses and temperatures during chip removal, chip 
sliding on the rake face and sliding of the free surface on the chipped 
workpiece cause wear on the cutting tool [5]. Tool wear adversely up-
sets tool life, the machined surface quality, dimensional precision and 
ultimately the economy of the cutting process [6]. 
In order to keep up with the rising need for high levels of produc-
tivity in the machining industry, cutting and feed rates have to be 
increased. When cutting, naturally high temperatures are generated, 
which not only shortens the life of the tool but also decreases the product 
quality. The utilization of cutting fluids, which are characterized by 
advantageous machining, lubricating, and cooling qualities, makes a 
constructive role to the overall machining performance [7]. However, a 
negative aspect of cutting fluids is that the quality decreases with use. 
Cutting fluids become contaminated with foreign substances over time. 
When the fluid loses its function, it becomes waste [8]. As a result, the 
* Corresponding author at: Faculty of Mechanical Engineering, Opole University of Technology, 76 Proszkowska St., 45-758 Opole, Poland. 
E-mail address: m.gupta@po.edu.pl (M.K. Gupta). 
Contents lists available at ScienceDirect 
Journal of Manufacturing Processes 
journal homepage: www.elsevier.com/locate/manpro 
https://doi.org/10.1016/j.jmapro.2023.08.026 
Received 1 April 2023; Received in revised form 27 June 2023; Accepted 9 August 2023 
mailto:m.gupta@po.edu.pl
www.sciencedirect.com/science/journal/15266125
https://www.elsevier.com/locate/manpro
https://doi.org/10.1016/j.jmapro.2023.08.026
https://doi.org/10.1016/j.jmapro.2023.08.026
https://doi.org/10.1016/j.jmapro.2023.08.026
http://crossmark.crossref.org/dialog/?doi=10.1016/j.jmapro.2023.08.026&domain=pdf
http://creativecommons.org/licenses/by/4.0/
Journal of Manufacturing Processes 103 (2023) 156–167
157
expenditures made for cutting fluids in companies constitute a large part 
of the total machining cost. Fluid expenses account for between 7 % and 
17 % of overall production costs, whereas tooling costs account for just 
4 % [9]. This disparity has recently begun to shift. Installing a fluid 
supply system, purchasing fluid, maintaining the system, and treating 
fluid waste are all examples of fluid-related costs. Reducing the amount 
of fluid used can result in substantial cost and waste savings, as high- 
output manufacturing facilities often use multiple cutting fluid reser-
voirs, each containing thousands of gallons of cutting fluid. When 
quality issues arise, it is not uncommon for an entire reservoir to be 
flushed to clean the system [9]. 
Three techniques are used for reducing the use of cutting fluid. These 
are cutting without using cutting fluid (dry cutting), especially high- 
speed cutting (High Speed Machining) and minimum quantity lubrica-
tion (MQL) techniques [10]. Although dry cutting is currently being 
used successfully as an environmentally friendly manufacturing method, 
this method may be less efficient when high machining efficiency, 
superior surface quality and difficult cutting situations are desired. For 
such cases, a MQL method, also called near dry machining, has been 
developed [11]. Moreover, the methods for increase of viscosity can be 
tried for thicker oil film between the workpiece and the cutting tool 
[12]. There are two options: i) increase base oil viscosity by adding 
nanoparticles into it (nano-lubricants / nano-MQL), ii) increase base oil 
or nano-MQL viscosity by decreasing the temperature of the oils [13]. In 
nanofluids formed from nanoparticles larger than 10 nm, the viscosity 
increases as the concentration increases, and decreases as the temper-
ature rises [14]. However, the viscosity value of the nanofluid is always 
high to the base fluid. Reducing the size of the nanoparticles for a given 
concentration increases the viscosity as it creates a higher solid surface 
area. 
Some literature studies about machining under different cutting 
environments like MQL [15], cryogenic [16] and hybrid cooling/lubri-
cation [17] are summarized below. Gajrani [18] performed Ti6Al4V 
turning via uncoated carbide under dry, MQL, and cryo-MQL conditions. 
Table 1 
Thechemical composition of the Inconel 601. 
Ni(%) Cr(%) S(%) Mn(%) Al(%) C(%) Cu(%) Si(%) Fe(%) 
~58–63 ~21–25 ~0.015 ~0.01 ~1.0–1.70 ~0.01 ~1.00 ~0.50 Bal. 
Fig. 1. Experimental setup used in the work. 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
158
The authors evaluated that the surface quality, insert wear and cutting 
forces decreases with cryo-MQL condition. Nagaraj et al. [19] conducted 
drilling experiments of CFRP composite via dry, MQL, cryogenic, and 
cryo-MQL environments. They assessed the surface quality, tool life is 
better under cryogenic, and cryo-MQL conditions than dry and MQL 
cutting environments. Khan et al. [20] performed turning experiments 
for Ti6Al4V via cemented carbide tools in MQL, flood, and cryo-MQL 
environment. The authors emphasized that surface roughness, insert 
wear and energy consumption can be decreased via cryo-MQL cooling/ 
lubrication condition. Sun et al. [21] performed the end milling of 
GH4099 superalloy in dry and MQL environments and highlighted MQL 
is better than dry conditions based on surface quality, insert wear and 
cutting force. 
In the light of the given information, the studies about insert wear in 
machining are generally based on comparison between dry, MQL, 
cryogenic, or cryo-MQL. In addition to these known procedures, as a 
novelty, this study also focused on using both different types of nano- 
MQL and cryogenic nano-MQL to rise the viscosity of the base oil (for 
thicker oil film) as well as to decrease the friction and heat between the 
workpiece and the insert. In this context, detail tool wear analysis and 
mechanisms, also different observations of critical tool flank and crater 
wear were evaluated in environmentally friendly turning of nickel-based 
superalloy. Moreover, roughness of the machined surface, chip 
morphology, microstructures and microhardness of machined work-
piece have also been analyzed. Finally, comprehensive images of SEM 
and also EDX/MAP analysis were performed for the evaluations of insert 
wear. 
2. Materials and methods 
In the experiments, commercially available Inconel 601 Ø60×200 
mm was used. The chemical composition of the material are presented in 
Table 1. Machining experiments were carried out using a Taksan- 
TTC550 CNC lathe in the Manufacturing Engineering laboratory of 
Karabük University. Kyocera brand carbide cutting inserts (CNMG 12 04 
04-MF) were used in the experiments. The experimental equipment is 
displayed in Fig. 1. The cutting parameter levels and carbide insert 
specifications are tabulated in Table 2. Werte branded WErtex15 model 
cooling system, which is suitable for external cooling applications, is 
used as the MQL system. This system is suitable for almost all work-
benches and enables experiments to be carried out easily. To increase 
the performance of the MQL system, 0.2 % nanoparticles were added to 
the cutting oil by suggestion of some literature studies [22]. Graphene 
and hBN nanoparticles were used to prepare nanofluids in the study. In 
addition, a total of 0.2 % nanoparticle (graphene 0.1 % + hBN 0.1 %) 
was added to obtain a hybrid nanofluid. While preparing the nanofluid 
to deliver the nanoparticles in equal numbers per unit area, the nano-
particles were supplied in close sizes and added to the cutting fluid on a 
weight basis. The hBN used is a white fluffy light powder with a large 
surface area, 40–50 nm in size. 
2.1. Testing procedure/sequence 
✓ Solid nanoparticles were added to the Werte branded WerteOil 
vegetable-based oil. The company of Werte Oils suggested this type 
of vegetable oil for cutting nickel-based superalloys. 
✓ Magnetic stirring, mechanical mixing and ultrasonic mixing pro-
cesses were applied to the nanoparticle added mixture in order to 
make the nanofluid mixture homogeneous. Thus, a homogeneous 
and delayed collapse nanofluid was obtained. The homogeneous 
nanofluid has been directly used after mixing. 
✓ Precision Balance was used for nanoparticle and MQL coolant 
amount variations. 
✓ LN2 cooling at 0.2 bar is supported for cryogenic cooling produced 
by Low-Temp Company. The lubrication and cooling environments 
named as MQL, nano-MQL, cryo and cryo-nano-MQL system are 
shown in Fig. 1. 
✓ Turning tests have been performed with mentioned cutting 
parameters. 
✓ The machine setup has been cleaned after each step of turning 
process. 
✓ Surface roughness measurements were done based on ISO 4287 
standard. Arithmetical mean roughness height (Ra) values were 
taken into account. The surface roughness measuring device used is 
the Mahr Perthometer-M300 branded portable measuring device. 
✓ Tool images by Scanning Electron Microscope (SEM) has been per-
formed by Nikon-Carl Zeiss branded SEM device and also Energy- 
dispersive X-ray spectroscopy (EDX) and MAP demonstration has 
been performed to understand better the adhesive and abrasion sit-
uations on the cutting inserts. 
✓ The samples prepared to take the microstructure image were 
immersed in a Inconel etchant consisting of Nitric Acid, Hydrochloric 
acid, H2O2 (30 %), Distilled Water by 50 ml, 75 ml, 35 ml, 90 ml for 
25 s, respectively. 
✓ The measurement of microhardness for the samples have been per-
formed by Qness branded Vicker Microhardness test setup. 
3. Results and discussions 
3.1. Tool wear 
The most commonly considered indicator in assessing tool life is 
Table 2 
The cutting parameter levels and carbide insert specifications. 
CCuuttttiinngg 
ppaarraammeetteerrss 
LLeevveellss 
CCuuttttiinngg ssppeeeedd 60 80 100 
FFeeeedd rraattee 0.8 0.12 
DDeepptthh ooff ccuutt 0.25 
CCuuttttiinngg mmeeddiiaa Dry MQL 
Nano-
MQL1 
(graphene) 
Nano-
MQL2 
(hBN) 
Nano-
MQL3 
(graphene 
+ hBN) 
Cryo 
Cryo-
nano-
MQL 
CCaarrbbiiddee iinnsseerrttss CNMG120404-PM4225 – Tool nose radius 0.4 mm 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
159
flank wear (Vb) and crater wear as displayed in Fig. 2. Fig. 3 displays the 
flank wear changes according to the cutting parameters thereafter 8 min 
turning of the workpiece under different cutting regimes. After 8 min, 
the tool was worn at the dry condition. That duration has been deter-
mined as the base duration in turning operations. The turning process at 
the other environments has been performed by 8 min for comparison. In 
general, it is understood that the flank wear tends to be similar in terms 
of cutting regimes at both feed rates. The increment in feed rate in-
creases the chip cross-section, increasing the cutting resistance and thus 
the mechanical loads to which the tool is exposed. As a result, the 
increased abrasive wear mechanism, especially in dry cutting, causes 
acceleration of flank wear [23]. In the presented study, the high Vb 
values in the dry cutting regime are attributed to the rapid removal of 
the tool coating owing to the large thermo-mechanical effect during 
cutting and the subsequent formation of Built-up-Edge (BUE). The 
increased ductility of the machined material is a direct result of the high 
temperatures generated during dry cutting. This is because the 
machined material has a limited heat conductivity and a property that 
causes it to strain harden. Because of this process, there was a greater 
rise in the development of BUE along the adhesive wear mechanism, 
namely the insert edge. That is to say, since there was no impact of 
cooling or lubrication present during this regime, the process of flank 
wear was accelerated by going througha cycle of development and 
rupture of the BUE. From Fig. 3, it is observed that Vb values increment 
proportionally with 50 % rise in feed. In this context, the maximum Vb 
was measured as 244 μm in dry cutting environment at 100 m/min 
cutting speed and 0.12 mm/rev feed. It is seen that the flank wear rises 
with increasing the cutting speed, and in the literature, this result is 
attributed to the rising temperature with increasing the cutting speed. 
When the Fig. 3 is examined carefully, the effect of increasing cutting 
speed becomes more evident in dry, MQL and Nano-MQL2 cutting re-
gimes at f = 0.08 mm/rev. Namely, increasing friction time at low feed 
causes the shear temperature to increase further, resulting in a decrease 
in the viscosity of the MQL fluid. This formation resulted in increased 
wear of Vb by reducing the lubricating film in MQL and the lubricating 
and microbedding effect in Nano-MQL2. As a matter of fact, the highest 
Fig. 2. The formation of flank and crater wear in a cutting insert. 
0
40
80
120
160
200
240
280
To
ol
w
ea
r,
µ
m
Cooling conditions
Dry_ MQL nano_MQL_1 nano_MQL_2 nano_MQL_3 Cryo_ Cryo_Nano_MQL
60 80 100
Cutting speed, m/min
0
40
80
120
160
200
240
280
To
ol
w
ea
r,
µm
60 80 100
Cutting speed, m/min
Feed rate: 0.08 mm/rev Feed rate: 0.12 mm/rev
Fig. 3. Tool wear values under different cutting conditions. 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
160
Fig. 4. Tool wear SEM (with EDX and MAP) under different cutting environments at the cutting speed of 100 m/min and the feed rate of 0.12 mm/rev. 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
161
Vb value after dry cutting was measured as 194 μm in MQL cutting 
medium at V = 100 m/min and f = 0.12 mm/rev. Among the nano-
particle cutting regimes, the lowest Vb values were obtained in the 
Nano-MQL-mix medium. In the presented study, the increase in chip-
ping and breakage on the cutting-edge following flank wear can be 
ascribed to the polishing/rubbing effect of nanoparticles. As expected, 
Vb values were lower due to the cooling effect providing by the Cryo and 
Cro-MQL regimens. The lowest Vb value (90 μm) is a result of the 
coolant effect of the Cry-MQL regime, keeping the cutting temperature 
at a reasonable level and thus not losing the lubricant performance of the 
MQL. 
Further, the tool wear mechanism with the help of SEM and EDX 
analysis was performed on the worn cutting tools, as shown in Fig. 4. 
The results of SEM images taken from the tool rake surfaces show the 
presence of Built-up-Layer (BUL) and BUE formations in all cutting 
regimes. It is seen that BUL formation is more concentrated in the 3rd 
region (sticking) of the rake face with increasing feed, which can be 
ascribed to the increment in the adhesion tendency with decreasing 
temperature towards the said region [24,25]. Indeed, EDX analyzes from 
different parts of the teams confirm these inferences. However, BUL 
formation appears to be lower in the MQL regimen than in other shear 
media. From this, it can be said that the lubricating film-forming prop-
erty of the cutting medium is more efficient than the high cutting speed 
in reducing the formation of BUL and BUE. The lubricating film layer 
formed at tool-chip contact surface in Nano-MQL and Cryo cutting re-
gimes reduced the abrasive wear effect and reduced the Vb value, as 
mentioned in the literature [26]. Moreover, as can be realized from 
Fig. 4, it is seen that especially in cutting environments with Nano-MQL, 
the fractures are concentrated at the crossing of the tool rake and flank 
surface. In the literature, the rubbing effect of particles in nanoparticle 
Fig. 4. (continued). 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
162
reinforced shear regimes is mentioned [27]. 
3.2. Surface roughness analysis 
Arithmetical mean roughness height (Ra) is the most considered 
roughness criterion in terms of both mechanical properties and surface 
integrity of machined parts. The surface roughness changes during 
turning of Inconel601 alloy in seven different cutting regimes are pre-
sented in Fig. 5. The primary thing to notice is that Ra values increase 
with increment feed from 0.08 mm/rev to 0.12 mm/rev, as expected. 
The 50 % increase in feed resulted in 60 % and 68 % increases in surface 
roughness at the minor cutting speed in dry and MQL cutting regimes, 
while this ratio was 136 % and 112 % at the major cutting speed. In 
Nano-MQL, Cryo and Cryo-MQL cutting environments, the rate of in-
crease in Ra value is over the range 100–114 % at the lowest cutting 
speed, while these rates are in over the range 86–93 % at the highest 
cutting speed. That is, the lubrication and/or cooling effect provided by 
Nano-MQL, Cryo and Cryo-MQL cutting media at high cutting speed 
resulted in a reduction in Ra values [28,29]. As it is well known from the 
literature [30], the Ra value changes in direct proportion to the feed in 
turning operations (Ra = f2/32r, r = nose radius). Another reason is that 
more machining scars are formed on the machined surface due to 
improved tool flank wear with increasing feed and cutting speed. When 
Fig. 5a and b are observed, it is clearly understood that Ra values in-
crease with increasing cutting speed in all cutting regimes. This result 
can be explained by the machining process, where increased cutting 
speed and feed cause peeling of the tool coating and subsequently 
accelerating tool wear. While the rise in cutting speed is expected to 
reduce the formation of BUE, high temperatures accelerate tool wear 
and the increase in friction and pressure in the tool-workpiece interface 
increased the tendency of chip adhesion. As can be observed from Fig. 4, 
the increased BUE on the tool flank and rake face caused a change in the 
active rake angle of the insert and an unstable cutting process, resulting 
in a decrease in surface quality, as mentioned by Pervaiz et al. [31]. 
Therefore, in both feeds, the worst surface quality occurred in the dry 
cutting regime, while the highest Ra value was 1.80 μm at V = 100 m/ 
min and f = 0.12 mm/rev. On the other hand, it is seen that the 
roughness decreases from the dry cutting regime to the Cryo-MQL 
regime, and this result is more pronounced at high feed. Thanks to the 
more lubricating effect of MQL and nano-MQL media, cutting occurs 
more easily in the second deformation zone (tool-chip interface), as 
contact length and thus frictional resistance are reduced [32]. This 
formation improves surface roughness as can be shown in Fig. 6 (a) and 
(b) by reducing cutting forces and tool vibrations. A similar formation 
occurs with the cooling influence providing in the Cryo cutting regime 
by Fig. 6c. The reduction in chip bend radius and segmentation ratio due 
to cooling, and thus the reduction in tool-chip interface friction resis-
tance, resulted in an improvement in roughness. Since this phenomenon 
prominently appeared in the Cryo-MQL medium, the minimal surface 
roughness was measured as 0.36 μm at a cutting speed of 60 m/min and 
feed of 0.08 mm/rev. 
3.3. Chip morphology 
Factors such as the chip type formed during the machining, the type 
of material removed, the tool geometry, the chip removal method 
applied,and the cutting parameters constitute a factor in the formation 
of the shape of the removed chips [33]. The types of chips formed also 
give us information about cutting conditions, whether chip removal is 
difficult or easy, and surface quality. In the case of machining ductile 
materials like nickel based superalloys with low or medium cutting 
speeds (dry machining), it caused the workpiece to stick to the cutting 
edge of the machining surface to a certain extent (BUE) due to the 
rubbing on the surface between the tool and chip [34]. This formation 
occurred in the form of a cycle and the bond between the tool weakened 
and broke [35]. The accumulation of chip during machining of Inconel- 
601 and the rupture of the formed accumulation occurred in a short 
time, and a large amount of plastered chips (Table 3) covered the 
machined surface [36]. At the end of the adhesion, it caused a notch 
effect on the machined surface, causing the surface quality to 
(a) (b)
Cutting speed, m/min
0.3
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
Su
rf
ac
e
ro
u
gh
n
es
s,
µm
Cooling conditions
Dry_
MQL
nano_MQL_1
nano_MQL_2
nano_MQL_3
Cryo_
Cryo_Nano_MQL
60 80 100
Cutting speed, m/min
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Su
rf
ac
e
ro
ug
hn
es
s,
µm
Cooling conditions
Dry_
MQL
nano_MQL_1
nano_MQL_2
nano_MQL_3
Cryo_
Cryo_Nano_MQL
60 80 100
Fig. 5. Surface roughness under cutting environments; (a) f = 0.08 mm/rev and (b) f = 0.12 mm/rev. 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
163
deteriorate. The continuous chips have occurred caused by the low 
friction between the tool and chip by the help of MQL, all of nano-MQL 
situations and also cryo-nano-MQL conditions [37]. When ductile ma-
terials like Inconel-601 are machined, the plastic deformation that oc-
curs in the material was caused by the sliding of many crystals on the 
shear plane. The occurrence of these chips showed us that a workpiece 
with a good surface quality was formed with MQL, nano-MQL and cryo- 
nano-MQL conditions [18], and this is seen in Table 3. In metals with 
low thermal conductivity, serrated chips were formed due to the rapid 
decrease in strength due to the increase in temperature during 
processing. The developments in the material types and cutting tool 
materials have caused the formation of serrated chip type in dry envi-
ronments without lubrication and cooling. Serrated chip formation has 
occurred in machining operations such as nickel-based alloys with low 
thermal conductivity, where the cutting process is performed in difficult 
and non-lubricated environments (dry machining) [38]. 
3.4. Microstructure and microhardness 
Machining is a serious plastic deformation process that leads to 
Fig. 6. Machined surface SEM images under different machining environments (a) Dry and MQL conditions, (b) Nano-MQL environment (c) Cryo and Cryo-Nano- 
MQL environment at the cutting speed of 100 m/min and the feed rate of 0.12 mm/rev. 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
164
alteration of microstructure and material features as a result of hetero-
geneous thermo-mechanical deformation of metal at high deformation 
rates [39]. After machining, the mechanical behavior of material based 
on considerations such as microstructure, stress and strain state, and 
these parameters are caused by thermal changes that change according 
to the cutting conditions [40]. In this context, estimation of thermo-
mechanical changes is important when machining difficult-to-machine 
materials under sustainable cutting regimes [41]. The microstructure 
images taken from the machined surfaces after 8 min turning on Inconel 
601 alloy are given in Fig. 7. 
Table 3 
Chip morphology under different machining environments. 
Sr. no. Cooling condition Types of chips Image of chips SEM images of chips 
1 Continuous chip 
(Entanglement) 
2 Continuous chip 
(Entanglement) 
3 Continuous chip 
(Entanglement) 
4 Continuous spiral chip 
5 Continuous spiral chip 
6 Discontinuous chip 
(Entanglement) 
7 Discontinuous spiral chip 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
165
The maximum hardness was obtained at 100 μm depth from the 
machined surface in all cutting environments, the highest microhard-
ness was 256 μm in the Cryo cutting regime, while the lowest micro-
hardness was found at 200 μm in the dry environment (Fig. 8). The high 
microhardness near the machined surface is the outcome of thermo- 
mechanical loads during cutting and strain hardening as a result of 
plastic deformation [43]. The excessive cutting temperature in the dry 
cutting environment caused softening in the material, preventing 
hardening due to plastic deformation as well as a coarser grained 
structure. As can be seen from Fig. 8, the fine-grained microstructure 
near the machined surface in a dry and MQL environment is an indi-
cation of the increase in microhardness. Grain thinning is a combination 
of hardness transformation temperature and plastic deformation, which 
varies depending on cutting parameters and environments, as 
mentioned in the literature [44]. At this point, the small thermal con-
ductivity of the work material means that the heat generated in the 
cutting zone is reduced in propagation towards the material core. Thus, 
more severe plastic deformation occurs near the surface, contributing to 
the formation of fine-grained structure. On the other hand, the increase 
in material tensile strength due to the sudden cooling provided by the 
Cryo and MQL cutting regimes also means an increase in plastic defor-
mation. In this case, the fine-grained structure will cause an increase in 
microhardness, again close to the machined surface. It is thought that 
the above-mentioned phenomenon occurs thanks to the heat carrying 
capacity of the particles in nano-MQL environments. As a matter of fact, 
the microhardness values obtained in these environments are between 
Cryo and pure MQL cutting regime. 
4. Conclusions 
During the turning of Inconel 601, the purpose of this research was to 
explore the influence that various cooling approaches have on the 
temperature of the tool-chip contact, surface roughness, and tool wear. 
The purpose of the study was to evaluate the practicability of cooling 
technology from a technical and ecological standpoint. Throughout the 
course of the studies, a variety of various approaches to cooling were 
utilized, including dry, MQL, nMQL (graphene, hBN, graphene+hBN), 
cryo-LN2, and hybrid conditions. The results of the experiment were 
analyzed in depth and the following findings were reached: 
• The application of cooling techniques during turning has greatly 
improved the machining performance of Inconel 601. With cryo- 
nMqL condition, there has been a noticeable decrease in flank 
wear. Due to the chilling effect of the Cryo and Cryo-nMQL C/L 
régimes, Vb values were lower as was to be predicted. Based on SEM 
analysis, tool flank wear under dry condition shows adhesion and 
severe wear. NMQL3, among nanofluid condition reduced the wear 
mechanisms by reducing the tool-work junction friction. However, 
the best condition to reduce the wear was cryo-NMQL. 
• The rate of rise in Ra value in the Nano-MQL, Cryo, and Cryo-MQLcutting settings ranges from 100 to 114 % at the minimal cutting 
speed to 86 to 93 % at the maximum cutting speed. In other words, 
Ra values diminished of the lubricating and/or cooling impact given 
by Nano-MQL, Cryo, and Cryo-nMQL cutting media. Dry and MQL 
produces highest Ra value in relation to other conditions. 
• With the aid of MQL, all nano-MQL scenarios, and cryo-nano-MQL 
conditions, continuous chips have developed as a result of the 
reduced friction amid the tool and the chip. 
• A coarser grained structure and hardening owing to plastic defor-
mation was prevented by the material softening in consequence of 
the dry cutting environment's high cutting temperature. However, 
the abrupt chilling and lubrication brought on by the Cryo and nMQL 
cutting regimes, which increases material tensile strength, simulta-
neously causes a rise in plastic deformation. In this instance, the 
microhardness will rise as a result of the fine-grained structure. 
Fig. 7. Microstructure images under the different cutting environments (Modified from [42]). 
M.E. Korkmaz et al. 
Journal of Manufacturing Processes 103 (2023) 156–167
166
Declaration of competing interest 
The authors declare the following financial interests/personal re-
lationships which may be considered as potential competing interests: 
The work presented in this paper is, to the best of my knowledge and 
belief, original, except as acknowledged in the text, and the material has 
not been submitted, either in whole or in part, for a degree at this or any 
other university. There is no conflict of interest to declare. 
Acknowledgement 
The authors thank to Karabük University Scientific Research Projects 
Coordination with a project number KBÜBAP-22-DS-141. 
References 
[1] Sugihara T, Kobayashi R, Enomoto T. Direct observations of tribological behavior 
in cutting with textured cutting tools. Int J Mach Tools Manuf 2021:103726. 
https://doi.org/10.1016/j.ijmachtools.2021.103726. 
[2] Rajashekhar Reddy S, Kumar MS, Vasu V. Temperature study in turning Inconel- 
718: 3D simulation and experimentation. Mater Today Proc 2017;4:9946–50. 
https://doi.org/10.1016/j.matpr.2017.06.299. 
[3] Yan P, Rong Y, Wang G. The effect of cutting fluids applied in metal cutting 
process. Proc Inst Mech Eng Part B J Eng Manuf 2015;230:19–37. https://doi.org/ 
10.1177/0954405415590993. 
[4] Demirsöz R, Boy M. Measurement and evaluation of machinability characteristics 
in turning of train wheel steel via CVD coated-RCMX carbide tool. Manuf Technol 
Appl 2022;3:1–13. https://doi.org/10.52795/mateca.1058771. 
[5] Thellaputta GR, Chandra PS, Rao CSP. Machinability of nickel based superalloys: a 
review. Mater Today Proc 2017;4:3712–21. https://doi.org/10.1016/J. 
MATPR.2017.02.266. 
[6] Escaich C, Shi Z, Baron L, Balazinski M. Machining of titanium metal matrix 
composites: progress overview. Mater 2020:13. https://doi.org/10.3390/ 
ma13215011. 
[7] Çakır Şencan A, Çelik M, Selayet Saraç EN. The effect of nanofluids used in the 
MQL technique applied in turning process on machining performance: a review on 
eco-friendly machining. Manuf Technol Appl 2021;2:47–66. https://doi.org/ 
10.52795/mateca.1020081. 
[8] Panda AK, Singh RK, Mishra DK. Thermolysis of waste plastics to liquid fuel. A 
suitable method for plastic waste management and manufacture of value added 
products-a world prospective. Renew Sust Energ Rev 2010:14. https://doi.org/ 
10.1016/j.rser.2009.07.005. 
[9] Adler DP, Hii WW-S, Michalek DJ, Sutherland JW. Examining the role of cutting 
fluids in machining and efforts to address associated environmental/health 
concerns. Mach Sci Technol 2006;10:23–58. https://doi.org/10.1080/ 
10910340500534282. 
[10] Gunjal SU, Sanap SB, Patil NG. Role of cutting fluids under minimum quantity 
lubrication: an experimental investigation of chip thickness. Mater Today Proc 
2019;28:1101–5. https://doi.org/10.1016/j.matpr.2020.01.090. 
[11] Pereira O, Rodríguez A, Fernández-Abia AI, Barreiro J, López de Lacalle LN. 
Cryogenic and minimum quantity lubrication for an eco-efficiency turning of AISI 
304. J Clean Prod 2016. https://doi.org/10.1016/j.jclepro.2016.08.030. 
[12] Ross NS, Ganesh M, Ananth MBJ, Kumar M, Rai R, Gupta MK, et al. Development 
and potential use of MWCNT suspended in vegetable oil as a cutting fluid in 
machining of Monel 400. J Mol Liq 2023;382:121853. https://doi.org/10.1016/j. 
molliq.2023.121853. 
[13] Çamlı KY, Demirsöz R, Boy M, Korkmaz ME, Yaşar N, Giasin K, et al. Performance 
of MQL and nano-MQL lubrication in machining ER7 steel for train wheel 
applications. Lubricants 2022;10:48. https://doi.org/10.3390/ 
lubricants10040048. 
[14] Zhang Y, Li C, Jia D, Zhang D, Zhang X. Experimental evaluation of MoS2 
nanoparticles in jet MQL grinding with different types of vegetable oil as base oil. 
J Clean Prod 2015;87:930–40. https://doi.org/10.1016/j.jclepro.2014.10.027. 
[15] Korkmaz ME, Gupta MK, Ross NS, Sivalingam V. Implementation of green cooling/ 
lubrication strategies in metal cutting industries: a state of the art towards 
sustainable future and challenges. Sustain Mater Technol 2023:e00641. 
[16] Chen X, Zhao W, Zhao G, Jamil M, He N. Tool wear and surface quality during 
milling CFRP laminates under dry and LN2-based cryogenic conditions. Int J Adv 
Manuf Technol 2022;123:1785–97. https://doi.org/10.1007/s00170-022-10234- 
y. 
[17] Jamil M, Iqbal A, He N, Cheok Q. Thermophysical properties and heat transfer 
performance of novel dry-ice-based sustainable hybrid lubri-coolant. Sustainability 
2022;14:2430. https://doi.org/10.3390/su14042430. 
0 100 200 300 400 500 600 700
Depth frommachined surface (µm)
160
180
200
220
240
260
M
ic
ro
ha
rd
ne
ss
(H
V)
Cooling conditions
Dry
MQL
nano_MQL1
nano_MQL2
nano_MQL3
Cryo_Nano_MQL
Cryo
Fig. 8. Micro-hardness values based on cutting conditions. 
M.E. Korkmaz et al. 
https://doi.org/10.1016/j.ijmachtools.2021.103726
https://doi.org/10.1016/j.matpr.2017.06.299
https://doi.org/10.1177/0954405415590993
https://doi.org/10.1177/0954405415590993
https://doi.org/10.52795/mateca.1058771
https://doi.org/10.1016/J.MATPR.2017.02.266
https://doi.org/10.1016/J.MATPR.2017.02.266
https://doi.org/10.3390/ma13215011
https://doi.org/10.3390/ma13215011
https://doi.org/10.52795/mateca.1020081
https://doi.org/10.52795/mateca.1020081
https://doi.org/10.1016/j.rser.2009.07.005
https://doi.org/10.1016/j.rser.2009.07.005
https://doi.org/10.1080/10910340500534282
https://doi.org/10.1080/10910340500534282
https://doi.org/10.1016/j.matpr.2020.01.090
https://doi.org/10.1016/j.jclepro.2016.08.030
https://doi.org/10.1016/j.molliq.2023.121853
https://doi.org/10.1016/j.molliq.2023.121853
https://doi.org/10.3390/lubricants10040048
https://doi.org/10.3390/lubricants10040048
https://doi.org/10.1016/j.jclepro.2014.10.027
http://refhub.elsevier.com/S1526-6125(23)00801-0/rf0075
http://refhub.elsevier.com/S1526-6125(23)00801-0/rf0075
http://refhub.elsevier.com/S1526-6125(23)00801-0/rf0075
https://doi.org/10.1007/s00170-022-10234-y
https://doi.org/10.1007/s00170-022-10234-y
https://doi.org/10.3390/su14042430
Journal of Manufacturing Processes 103 (2023) 156–167
167
[18] Gajrani KK. Assessment of cryo-MQL environment for machining of Ti-6Al-4V. 
J Manuf Process 2020;60:494–502. https://doi.org/10.1016/j. 
jmapro.2020.10.038. 
[19] Nagaraj A, Uysal A, Gururaja S, Jawahir IS. Analysis of surface integrity in drilling 
carbon fiber reinforced polymer composite material under various cooling/ 
lubricating conditions. J Manuf Process 2022;82:124–37.https://doi.org/ 
10.1016/j.jmapro.2022.07.065. 
[20] Khan AM, He N, Li L, Zhao W, Jamil M. Analysis of productivity and machining 
efficiency in sustainable machining of titanium alloy. Procedia Manuf 2020;43: 
111–8. https://doi.org/10.1016/j.promfg.2020.02.122. 
[21] Sun H, Zou B, Chen P, Huang C, Guo G, Liu J, et al. Effect of MQL condition on 
cutting performance of high-speed machining of GH4099 with ceramic end mills. 
Tribol Int 2022;170:107401. https://doi.org/10.1016/j.triboint.2021.107401. 
[22] Paturi UMR, Kumar GN, Vamshi VS. Silver nanoparticle-based tween 80 green 
cutting fluid (AgNP-GCF) assisted MQL machining - an attempt towards eco- 
friendly machining. Clean Eng Technol 2020;1:100025. https://doi.org/10.1016/j. 
clet.2020.100025. 
[23] Danish M, Gupta MK, Rubaiee S, Ahmed A, Korkmaz ME. Influence of hybrid Cryo- 
MQL lubri-cooling strategy on the machining and tribological characteristics of 
Inconel 718. Tribol Int 2021;107178. 
[24] Zhang T, Jiang F, Huang H, Lu J, Wu Y, Jiang Z, et al. Towards understanding the 
brittle–ductile transition in the extreme manufacturing. Int J Extrem Manuf 2021; 
3:022001. https://doi.org/10.1088/2631-7990/abdfd7. 
[25] Bushlya V, Lenrick F, Bjerke A, Aboulfadl H, Thuvander M, Ståhl J-E, et al. Tool 
wear mechanisms of PcBN in machining Inconel 718: analysis across multiple 
length scale. CIRP Ann 2021. https://doi.org/10.1016/j.cirp.2021.04.008. 
[26] Ross NS, Srinivasan N, Amutha P, Gupta MK, Korkmaz ME. Thermo-physical, 
tribological and machining characteristics of Hastelloy C276 under sustainable 
cooling/lubrication conditions. J Manuf Process 2022;80:397–413. https://doi. 
org/10.1016/j.jmapro.2022.06.018. 
[27] Mali HS, Unune DR. Machinability of Nickel-based Superalloys: An Overview. 
Elsevier Ltd.; 2017. https://doi.org/10.1016/b978-0-12-803581-8.09817-9. 
[28] Tuan NM, Ngoc TB, Le Thu T, Long TT. Investigation of the effects of nanoparticle 
concentration and cutting parameters on surface roughness in MQL hard turning 
using MoS2 nanofluid. Fluids 2021;6:398. https://doi.org/10.3390/ 
fluids6110398. 
[29] Baig A, Jaffery SHI, Khan MA, Alruqi M. Statistical analysis of surface roughness, 
burr formation and tool wear in high speed micro milling of Inconel 600 alloy 
under cryogenic, wet and dry conditions. Micromachines 2022;14:13. https://doi. 
org/10.3390/mi14010013. 
[30] Sivaiah P, Chakradhar D. The effectiveness of a novel cryogenic cooling approach 
on turning performance characteristics during machining of 17-4 PH stainless steel 
material. Silicon 2019;11:25–38. https://doi.org/10.1007/s12633-018-9875-3. 
[31] Pervaiz S, Kannan S, Anwar S, Huo D. Machinability analysis of dry and liquid 
nitrogen–based cryogenic cutting of Inconel 718: experimental and FE analysis. Int 
J Adv Manuf Technol 2022;118:3801–18. https://doi.org/10.1007/s00170-021- 
08173-1. 
[32] Wang X, Li C, Zhang Y, Ding W, Yang M, Gao T, et al. Vegetable oil-based nanofluid 
minimum quantity lubrication turning: academic review and perspectives. J Manuf 
Process 2020;59:76–97. https://doi.org/10.1016/j.jmapro.2020.09.044. 
[33] Xu J, El Mansori M, Voisin J, Chen M, Ren F. On the interpretation of drilling 
CFRP/Ti6Al4V stacks using the orthogonal cutting method: chip removal mode 
and subsurface damage formation. J Manuf Process 2019;44:435–47. https://doi. 
org/10.1016/j.jmapro.2019.05.052. 
[34] Özel T, Biermann D, Enomoto T, Mativenga P. Structured and textured cutting tool 
surfaces for machining applications. CIRP Ann 2021;70:495–518. https://doi.org/ 
10.1016/j.cirp.2021.05.006. 
[35] Grigoriev SN, Fedorov SV, Hamdy K. Materials, properties, manufacturing methods 
and cutting performance of innovative ceramic cutting tools − a review. Manuf Rev 
2019;6:19. https://doi.org/10.1051/mfreview/2019016. 
[36] Wojciechowski S, Matuszak M, Powałka B, Madajewski M, Maruda RW, 
Królczyk GM. Prediction of cutting forces during micro end milling considering 
chip thickness accumulation. Int J Mach Tools Manuf 2019;147:103466. https:// 
doi.org/10.1016/j.ijmachtools.2019.103466. 
[37] Yılmaz B, Karabulut Ş, Güllü A. A review of the chip breaking methods for 
continuous chips in turning. J Manuf Process 2020;49:50–69. https://doi.org/ 
10.1016/j.jmapro.2019.10.026. 
[38] Östby J, Toller-Nordström L, Norgren S. Insights into plastic deformation and 
binder lamella orientation in hardmetal turning inserts. Int J Refract Met Hard 
Mater 2022;103:105779. https://doi.org/10.1016/j.ijrmhm.2022.105779. 
[39] Liang X, Liu Z, Wang B, Hou X. Modeling of plastic deformation induced by 
thermo-mechanical stresses considering tool flank wear in high-speed machining 
Ti-6Al-4V. Int J Mech Sci 2018;140:1–12. https://doi.org/10.1016/j. 
ijmecsci.2018.02.031. 
[40] Zhang D, Zhang X-M, Nie G-C, Yang Z-Y, Ding H. Characterization of material 
strain and thermal softening effects in the cutting process. Int J Mach Tools Manuf 
2021;160:103672. https://doi.org/10.1016/j.ijmachtools.2020.103672. 
[41] Khan AM, Alkahtani M, Sharma S, Jamil M, Iqbal A, He N. Sustainability-based 
holistic assessment and determination of optimal resource consumption for energy- 
efficient machining of hardened steel. J Clean Prod 2021;319:128674. https://doi. 
org/10.1016/j.jclepro.2021.128674. 
[42] Liang X, Liu Z, Wang B. State-of-the-art of surface integrity induced by tool wear 
effects in machining process of titanium and nickel alloys: a review. Meas J Int 
Meas Confed 2019;132:150–81. https://doi.org/10.1016/j. 
measurement.2018.09.045. 
[43] Zhou B, Zhang W, Gao Z, Luo G. Machining-induced work hardening behavior of 
Inconel 718 considering edge geometries. Materials (Basel) 2022;15:397. https:// 
doi.org/10.3390/ma15020397. 
[44] Zhuang K, Hu C, Zhou J, Lin Peng R. Investigation on work hardening phenomenon 
in turning Inconel 718 with chamfered inserts considering thermal-mechanical 
loads. Procedia CIRP 2020;87:47–52. https://doi.org/10.1016/j. 
procir.2020.02.071. 
M.E. Korkmaz et al. 
https://doi.org/10.1016/j.jmapro.2020.10.038
https://doi.org/10.1016/j.jmapro.2020.10.038
https://doi.org/10.1016/j.jmapro.2022.07.065
https://doi.org/10.1016/j.jmapro.2022.07.065
https://doi.org/10.1016/j.promfg.2020.02.122
https://doi.org/10.1016/j.triboint.2021.107401
https://doi.org/10.1016/j.clet.2020.100025
https://doi.org/10.1016/j.clet.2020.100025
http://refhub.elsevier.com/S1526-6125(23)00801-0/rf0115
http://refhub.elsevier.com/S1526-6125(23)00801-0/rf0115
http://refhub.elsevier.com/S1526-6125(23)00801-0/rf0115
https://doi.org/10.1088/2631-7990/abdfd7
https://doi.org/10.1016/j.cirp.2021.04.008
https://doi.org/10.1016/j.jmapro.2022.06.018
https://doi.org/10.1016/j.jmapro.2022.06.018
https://doi.org/10.1016/b978-0-12-803581-8.09817-9
https://doi.org/10.3390/fluids6110398
https://doi.org/10.3390/fluids6110398
https://doi.org/10.3390/mi14010013
https://doi.org/10.3390/mi14010013
https://doi.org/10.1007/s12633-018-9875-3
https://doi.org/10.1007/s00170-021-08173-1
https://doi.org/10.1007/s00170-021-08173-1
https://doi.org/10.1016/j.jmapro.2020.09.044
https://doi.org/10.1016/j.jmapro.2019.05.052
https://doi.org/10.1016/j.jmapro.2019.05.052
https://doi.org/10.1016/j.cirp.2021.05.006
https://doi.org/10.1016/j.cirp.2021.05.006
https://doi.org/10.1051/mfreview/2019016
https://doi.org/10.1016/j.ijmachtools.2019.103466
https://doi.org/10.1016/j.ijmachtools.2019.103466
https://doi.org/10.1016/j.jmapro.2019.10.026
https://doi.org/10.1016/j.jmapro.2019.10.026
https://doi.org/10.1016/j.ijrmhm.2022.105779
https://doi.org/10.1016/j.ijmecsci.2018.02.031
https://doi.org/10.1016/j.ijmecsci.2018.02.031
https://doi.org/10.1016/j.ijmachtools.2020.103672
https://doi.org/10.1016/j.jclepro.2021.128674
https://doi.org/10.1016/j.jclepro.2021.128674
https://doi.org/10.1016/j.measurement.2018.09.045https://doi.org/10.1016/j.measurement.2018.09.045
https://doi.org/10.3390/ma15020397
https://doi.org/10.3390/ma15020397
https://doi.org/10.1016/j.procir.2020.02.071
https://doi.org/10.1016/j.procir.2020.02.071
	Comprehensive analysis of tool wear, surface roughness and chip morphology in sustainable turning of Inconel-601 alloy
	1 Introduction
	2 Materials and methods
	2.1 Testing procedure/sequence
	3 Results and discussions
	3.1 Tool wear
	3.2 Surface roughness analysis
	3.3 Chip morphology
	3.4 Microstructure and microhardness
	4 Conclusions
	Declaration of competing interest
	Acknowledgement
	References