Foundry

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FOUNDRY TECHNOLOGY or CASTING 
OF TECHNOLOGY 
FOUNDRY TECHNOLOGY 
DEFINITION 
A method of forming the material from the casting and solidification of 
the liquid metal into a mold or matrix, the dimensions and geometry of 
which reproduces the part to be obtained. 
LIQUID 
METAL LEAKING 
MOLD or 
MATRIX SOLIDIFICATION 
PART 
 Casting is a technology of forming metals or metal alloys, where 
the internal cavity of the mold or matrix reproduces the "negative" of 
the part, being an application of the principle of Archimedes: "a liquid 
takes the form of the container containing it " 
 The material is cast in suitable furnaces and cast in a 
TEMPORARY (disposable) or PERMANENT (durable) form resistant 
to pressure and heat of the cast metal. 
CHARACTERIZATION OF FOUNDRY TECHNOLOGY 
"Casting is the shortest path between the metallic raw 
material and the finished or almost permanent part, 
under conditions of use " 
 
OLD TECNOLOGY 
 
 
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* Dimensional accuracy and surface finish depending on the type of 
process used; 
* Used in the "melt-on" or "heat-treated or mechanically" conditions, 
depending on the material standard or customer specification, that is, 
 
Note: it can be used "casting or melting bricks" or heat, mechanical or thermo-
mechanical properties for the correctness of properties required for use, but not 
achieved in the crude state of casting may exhibit distortion, embrittlement due to 
residual stresses or cracking due to thermal stresses caused by temperature gradients 
during solidification and cooling; 
 
CHARACTERIZATION OF FOUNDRY TECHNOLOGY 
* Can be recovered by welding, if authorized by the product or 
customer standard; surface discontinuities can be filled by adhesives, 
resins or hardenable doughs only for superficial aesthetic situations, 
so as not to compromise the integrity, strength and service life of the 
part in service! 
* Quality controlled through testing and compliance testing, sanity, 
acceptability and functionality 
* Management in a context of Quality, Safety and Environment System 
CHARACTERIZATION OF FOUNDRY TECHNOLOGY 
Industrially or artistically employed to obtain products, machine parts 
or parts for mechanical, industrial and household purposes, with 
greater freedom of shape: simple or complex geometry / shape, small 
or large dimensions or thicknesses (up to 200 tons and minimum size 
limited to a few grams), flat or massive, with recesses and voids 
internal or open to the surface. 
INDUSTRIAL APPLICATION OF FOUNDRY 
 
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INDUSTRIAL APPLICATION OF FOUNDRY 
* Applicable to form virtually all types of metals and alloys used in 
engineering except high melting point materials such as tungsten, 
molybdenum and tantalum. 
* Unique option for manufacturing parts or components in cast iron, 
as this material can not be mechanically formed by rolling, forging or 
stamping. 
a) Semi-products: ingots with a simple geometry to be 
stored in the solid state for later remelting or that will 
be used for mechanical forming by means of plastic 
deformation by rolling, forging, extrusion, drawing for 
other shapes such as plates, strips, profiles and bars, 
to be machined, cut, welded or stamped. 
b) Parts: with basic and definitive shapes 
and geometries, which depict the desired 
final shape, being able to undergo 
modifications by machining, grinding and 
welding or alterations of properties by 
thermal or mechanical treatment. 
INDUSTRIAL APPLICATION OF FOUNDRY 
Examples: 
• hydraulic rotor, 
• Pelton type, Francis (5 ton) or rotor parts (spade, belt or hub), 
• Al or Mg alloy wheels for cars, 
• combustion engine block in cast iron or aluminum, etc. 
CASTING OF TECHNIQUES 
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INDUSTRIAL APPLICATION OF FOUNDRY 
Hydraulic rotor 
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INDUSTRIAL APPLICATION OF FOUNDRY 
Combustion engine block in cast iron or aluminum 
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INDUSTRIAL APPLICATION OF FOUNDRY 
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INDUSTRIAL APPLICATION OF FOUNDRY 
 
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INDUSTRIAL APPLICATION OF FOUNDRY 
Al or Mg alloy wheels for cars 
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INDUSTRIAL APPLICATION OF FOUNDRY 
* Typical sequence for temporary casting: 
 
model → molding → model extraction → mold → demoulding → cast 
part or semi-finished product 
 ↑ 
 leakage 
 ↑ 
 metal → fusion 
 
* Typical sequence for casting in permanent mold: 
 
 mold → demoulding → cast part or 
semi-finished product 
 ↑ 
 leakage 
 ↑ 
 metal → fusion 
 
ELEMENTS of FOUNDRY 
 Hand-crafted, by form, by conventional or rapid prototyping, in 
single piece or in several parts to facilitate the confection of the mold 
or its removal from the mold; may be definitive (used for various 
moldings) in metal, wood, synthetic resin, plaster or styrofoam and 
wax consumables. 
PATTERN or MODEL 
PATTERN or MODEL 
Prototype of the part used to shape and dimension the temporary mold 
cavity, reproducing the shape of the part with dimensions equivalent 
to the part (without overmold) or added / altered to compensate for 
the contraction of solidification of the metal, after cooling (with 
overmetall) and also for certain configurations of the model and / or 
part. 
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 The geometry and dimensions of the desired part or semi-
finished product are shown in "negative", matrix, form, tool, stamp, 
model plate, shell or ingot mold containing the cavity that portrays and 
corresponds in "negative". 
 The mold forming material must have sufficient mechanical 
strength and erosion resistance to withstand the action of the heat 
and / or pressure of the liquid metal therein without undoing or 
deforming. 
 
MOLD 
The classification: 
* Temporary mold: for example the green sand mold 
• made in order to configure the cavity, which corresponds to the part 
to be cast; 
• requires a model (pattern) for its preparation; 
• to remove the molten part from the inside; 
• made in cured sand, plaster, calcined material, cement or ceramic for 
a single use, being sacrificed, in the demolding 
 
 
MOLD 
MOLD 
* Permanent mold: for example the matrix 
• preserved after remove the part have being produced; made of 
ferrous metal (steel, cast iron) or non-ferrous (bronze, copper), 
being durable and reusable to melt several pieces, 
• without being destroyed, being therefore definitive; 
• does not require a model for its preparation, since its superficial 
relief is made by machining or electro erosion to obtain the 
"negative" forms, 
• without the conventional modeling and molding steps for temporary 
mold 
MOLD 
MOLD 
* Permanent mold: for example the matrix 
Mold Elements 
 
* temporary mold box: container to contain the molding material; may 
consist of several overlapping boxes depending on the size and geometry 
of the part to be cast 
* Model Plates: Permanent molding die mounted on a metal plate 
* Pouring cup or Leakage channel: conduit through which liquid metal 
that will fill the mold cavity is flowed or injected 
MOLD 
* Riser: extension of the mold, but which is not part of the part, 
positioned so as to finally solidify, directing the solidification in the 
mold. 
NOTE: (a) Liquid metal technical reserve, which holds the molten metal inside 
the mold at a "positive pressure", enabling the cast part within the mold to 
solidify according to the desired dimensions and geometry. 
(b) Secondary functions: visualize the filling level of the mold to indicate the 
end of the casting, enable the exit of gases or residues present inside the 
mold, placeto fix clamps for handling the part after demolding 
 
MOLD 
* Core 
• Part manufactured separately and placed inside the mold, after 
extraction of the model; 
• to form hollows or recesses in the interior or exterior of the cast; 
• this mold element is made by means of a core box, whose internal 
void is its negative, made with the same materials used in the 
models; 
• the recess in the mold where the core will lean or fit, if fixing, is 
called the CORE marking. 
MOLD 
MOLD 
* Core 
Characteristics of a casting core: 
 
* Mechanical strength: withstand pressures of liquid metal; 
 
* Permeability: to facilitate the escape of gases; 
 
* Refractoriness: withstand high temperatures; 
 
* Compressibility: withstand the expansion or contraction of the metal; 
 
* Collapsibility: not to oppose the contraction of the metal and ease of 
disassembly. 
* Core 
MOLD 
* Coolers or Chills: 
• Good heat conducting metals (high thermal conductivity) that make 
the temporary mold in certain positions to control the heat flow of 
the metal under cooling; 
• accelerating the solidification process and the cooling rate in a part 
of the part or locally, aiming avoid internal defects in the part or 
phenomena detrimental to the melt; 
• by rapid thermal exchange with the mold; in permanent metal molds, 
the mold itself performs these functions. 
MOLD 
MOLD 
* Insulators: 
• Refractory materials, located in certain positions of the temporary 
mold to allow slower cooling speed in a particular part or region of 
the part, delaying the solidification process; 
• leaving the metal molten longer in high temperature, aiming some 
benefit to the melt; 
• in temporary molds of sand, cement or plaster, the mold itself 
performs these functions 
MOLD 
* Sighs: ventilation holes or thieves where the air or gases present inside 
the mold or generated during the leakage are trapped, avoiding pores in the 
cast. 
MOLD 
These original properties can be altered by thermal or mechanical treatments. 
a) Casting: resulting from the solidification and cooling process of the 
liquid metal inside the mold, presenting a microstructure and 
heterogeneous chemical composition, conferring anisotropy to the 
part, with variable level of segregation and residual internal stresses; 
b) Thermally treated: resulting from post-cast heat treatments, giving 
the piece a microstructural and chemical homogeneity, with low level of 
residual stresses and, therefore, with isotropic characteristics 
c) Mechanically treated: resulting from mechanical treatments after 
casting, such as vibration or hardening, producing a part with properties 
dependent on these processes 
PROPERTIES OF A CAST 
The degree of quality and mechanical properties required of a casting 
will depend on the application and nature of the efforts to which it will 
be subjected in service: 
* Static loading 
* Dynamic loading by fatigue, shock, vibration, etc. 
 
PROPERTIES OF A CAST 
Cast iron: 
• Fe-C-Si ferrous alloy group with 2.5 to 4.0% C + 0.5 to 3.5% 
Si + additions of alloying elements (when it is desired to 
improve or impart some property to the base alloy); 
• because of their low ductility, they can not be formed 
mechanically: 
• by rolling, forging or other plastic deformation processes, and 
are therefore transformed into parts or components only 
through the smelting, hence the name "cast iron". 
METALS AND FERROUS METAL ALLOYS 
Cast iron: 
NOTE:They present as characteristics relatively low melting temperature, good 
wetting, low volumetric contraction due to solidification, mechanical properties 
defined by the chemical composition of the alloy + microstructure resulting from the 
cooling rate during and after solidification inside the mold or by thermal and/or 
mechanical treatments . 
METALS AND FERROUS METAL ALLOYS 
    
Hard Cast 
iron: 
cementite 
(Fe3C) 
Grey cast iron: 
graphite in 
shafts 
Nodular cast iron 
matrix hard cast 
iron 
+ carbon: graphite 
Spheroidal cast 
iron 
carbon: 
graphite on 
nodules or 
spheroids 
Cast iron 
↓ 
Mechanical properties 
↓ 
Chemical composition + Cooling microstructure 
METALS AND FERROUS METAL ALLOYS: 
METALS AND FERROUS METAL ALLOYS: 
White Cast Iron / Hard Cast Iron: 
• its production is a combination of chemical composition + high 
cooling rate, to suppress the graphitization, favoring the carbon 
stay in the matrix in the form combined with iron → Fe3C: 
Cementite. 
• The mold should be metal to accelerate the rate of cooling of the 
metal so as to obtain and control the depth of the quenched layer; 
METALS AND FERROUS METAL ALLOYS: 
Grey Cast Iron: 
• Exhibits properties that are a function of the chemical 
composition, shape and distribution of the free carbon in the form 
of graphite, in addition to the influence of the thickness of the 
part on the cooling rate in the casting mold; 
 
Notes: 
• It presents as characteristics a temperature range of fusion of 
1360 to 1380; 
• solid contraction of the order of half of the contraction of the 
carbon steels, minimizing the surplus to compensate dimensional 
loss and conferring lower level of thermal and / or residual 
stresses; 
METALS AND FERROUS METAL ALLOYS: 
• solid contraction of the order of half of the contraction of the 
carbon steels, minimizing the surplus to compensate dimensional 
loss and conferring lower level of thermal and / or residual 
stresses; 
• the precipitation of graphite promotes dilation during the cooling 
and solidification of the liquid, anomalous phenomenon that occurs 
theoretically for a graphite content of 3%, but in practice, other 
factors cause contractions in disagreement with what was 
predicted. 
METALS AND FERROUS METAL ALLOYS: 
Ductile Cast Iron / Nodular Cast Iron: 
• obtained from a white cast iron; 
• by post-casting malleability heat treatment to cause the 
transformation of some or all of the combined carbon into 
graphite; 
• making the material more ductile and toughness for various 
industrial applications such as connections for hydraulic piping and 
transmission electric, chains, spring brackets, steering or 
differential box, wheel hubs, shoes. 
METALS AND FERROUS METAL ALLOYS: 
Malleable Cast iron / Spheroidal Cast Iron: 
• the carbon is in the form of spheroidal graphite, which gives 
greater continuity to the matrix, resulting in greater ductility, 
toughness and mechanical strength. 
Notes: 
• It has as characteristics a melting temperature range of 1470 to 
1490 ° C; 
• a pearly matrix having a solid contraction of the order of 1.25%, 
but upon annealing, it may have a dilation of ~ 0.4%, whereas a 
ferritic matrix does not exhibit contraction. 
METALS AND FERROUS METAL ALLOYS: 
Cast alloys: 
• group of ferrous alloys with Cdeoxidizing, desulfurising or dephosphating elements, coke / coal, 
clay, resins 
(c) sand: analytical tests (determination of moisture and clay and 
granulometric analysis) and technological at room temperature (mechanical 
strength, permeability, hardness, deformation, flow and friability) and high 
temperature (collapsibility, compression, permeability, expansion and 
contraction ). 
FOUNDRY TESTS 
(a) Goals: 
 
* Melt and keep the liquid metal at the proper temperature for leakage 
 
* Formation of an alloy from its elementary constituents 
 
* Correction of the chemical composition to correct the percentage composition 
of the alloying elements 
 
* Refining of metal or alloy, for the elimination of impurities (sulfur, 
phosphorus and oxygen)refluxing of the metal ingot or alloy obtained by 
conventional furnaces to promote a progressive solidification, aiming at a 
more homogeneous macro / microstructure with low inclusions, 
segregation and porosity. The recast product has isotropic properties, 
with high dimensional stability under subsequent heat treatment and high 
and reproducible mechanical properties 
FUSING FURNACES 
(b) Types of Furnaces: 
They use various forms of heating such as by fuel (coke, oil and gas) or 
by electric energy (resistance, induction, electric arc), which 
characterize different types of furnaces: 
* Crucible: used to melt a defined amount of material; applicable to the 
production of alloys of Al, Cu, Ni, Pb, cast iron 
* Rotary: used to melt a defined amount of material; applicable to the 
production of copper alloys (brass and brass) 
* Reverb: Used to merge a defined amount of material; applicable to the 
production of Al and copper alloys (brass and brass, when the copper is 
melted and then the zinc is added) 
FUSING FURNACES 
(b) Types of Furnaces: 
* Cuba: cubilô (continuous or intermittent fusion for cast iron) and blast 
furnace (irons and first melts) for large quantities 
* Convertor or Converter: LD type or electric to arc, applicable to the 
production of steels in large quantities 
* Reflux: furnaces suitable for refining ingots through 
electroconductive slag, electron beam or arc under vacuum, aiming at 
refining and / or progressive solidification of the metal, for its 
purification and homogenization in terms of microstructure and chemical 
constitution, with low inclusions and segregation. 
FUSING FURNACES 
 
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FUSING FURNACES 
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FUSING FURNACES 
Forno cubilô: fabricação de ferro fundido 
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FUSING FURNACES 
 
 
Alto Forno: fabricação de ferro gusa 
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FUSING FURNACES 
 
Convertedores: fabricação de aço a partir do ferro gusa + sucata 
O2 
 
O2 
59 
Carregamento de gusa no convertedor 
Convertedores 
Sopro por cima 
Sopro por baixo 
FUSING FURNACES 
 
 
Forno elétrico: fusão de sucata 
60 
FUSING FURNACES 
FUSING FURNACES 
The leakage of liquid metal into the mold can be done by: 
* Gravity: the molten metal is cast into the mold under the action of 
the force of gravity 
* Pressure: 
- external mechanics: the molten metal is mechanically injected into 
the mold under pressure of a plunger of a device coupled to the mold; 
- centrifugation: the molten metal is injected into the mold under the 
dynamics of centrifugal forces (the mold rotates about an axis) 
LEAKAGE MOLDES 
TYPES OF THE LEAKAGE 
 
* Gravit 
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Tecnologia da Fundição 
TYPES OF THE LEAKAGE 
 
 
 
 
* Continuous 
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Types of leakages: 
 
Pressure 
 
 
 
 
 
 
 
 
 
65 
During casting, liquid metal may be in contact with ambient air 
under vacuum or controlled atmosphere. 
Types of leakages: 
♦ continuous: cast without interruption through a permanent mold 
→ the cast is produced continuously 
♦ Piece-to-Piece: Each die or piece is produced separately, in 
temporary or permanent mold, from a single mold or derived from 
a mold → serial or single-part production 
♦ Bypass: through a single leakage channel, the metal fills several 
molds at the same time 
LEAKAGE MOLDES 
* Casting temperature: the metal must be overheated to not 
solidify before occupying the entire interior of the mold and 
maintaining its proper viscosity; 
 * Leakage mode: turbulence of the flow of liquid metal inside 
the mold, causing erosion of the same and altering the dimensions 
and geometry of the piece, besides favoring the oxidation of the 
material 
Factors influencing the casting of the metal into the mold: 
LEAKAGE MOLDES 
• The obtaining of a casting involves phase change of the liquid material 
to solid; 
• Phenomena of exchange and transfer of heat between the metal and 
the mold. 
• As the liquid metal solidifies, the heat is dissipated and is led through 
the mold wall to the outside. 
FOUNDATIONS OF METALLIC ALLOYS SOLIDIFICATION 
The study of the solidification of a metallic material is considered: 
• the aspect of the energies involved, according to the 
thermodynamics and kinetics of the nucleation speed and grain 
growth, from a liquid. 
 
NOTE: 
It is a phenomenon that shows the "discipline" of atoms at the moment the 
system reaches the temperature of solidification → each atom "knows" its 
place in the space of the crystalline structure; some atoms are "disobedient" 
occupying undefined places, generating defects in the atomic arrangement. 
FOUNDATIONS OF METALLIC ALLOYS SOLIDIFICATION 
• A metal in the solid state has atoms that vibrate with certain 
frequency around well defined geometric positions; 
• determined by the type of crystalline arrangement characteristic 
of the material; 
• in the liquid state, besides vibrating, the atoms have no definite 
position, being in random motion. 
FOUNDATIONS OF METALLIC ALLOYS SOLIDIFICATION 
• In order to initiate the solidification, that is, transformation of 
the liquid metal to the solid state; 
• several atoms must group together forming an embryo, that when 
growing, will give rise to a nucleus, with a certain atomic 
arrangement, type CCC, CFC, HC, etc. , characteristic of each 
material. 
FOUNDATIONS OF METALLIC ALLOYS SOLIDIFICATION 
(a) Pure metals and eutectic alloys: 
They are solidified at constant temperature and equal to their 
solidification point (or melting point), presenting a typical cooling curve: 
Temperatura 
Tvazamento 
vazamento: estado líquido 
resfriamento do líquido 
início da solidificação 
fim da solidificação: estado sólido 
resfriamento do sólido 
Tempo 
Ponto de solidificação 
Tambiente 
SOLIDIFICATION OF METALS AND METALLIC ALLOYS 
(b) Metal alloys: 
They solidify in a temperature range or solidification (or melting) 
interval, whose typical curve of cooling would be: 
vazamento: estado líquido 
Diagrama de fase da liga metálica XY 
Temperatura 
Tvazamento 
resfriamento do líquido 
início da solidificação 
fim da solidificação: 
estado sólido 
resfriamen
to do 
sólido 
Tempo 
Líquido 
Sólido 
T 
Intervalo de 
solidificação 
da liga 
X (%) Y (%) 
L+S 
70 
Curva típica de resfriamento para uma liga metálica 30% X - 70% Y 
SOLIDIFICATION OF METALS AND METALLIC ALLOYS 
The melting involves phenomena characteristic of the evolution of 
the metal or liquid alloy until its complete solidification in the mold at 
room temperature: 
* nucleation and grain growth; 
* microstructure development; 
* chemical segregation; 
* occurrence of porosities or inclusions. 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
Note: 
• The gradual appearance of the first solid nucleus, called 
dendrites; 
• in the pure metals and zoned structure in the metal alloys, which 
will give rise to the future grains of the material, occurs next to 
the wall of the mold by homogeneous nucleation or from solid 
particles present in the liquid , by heterogeneous nucleation. 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
Nucleation: 
Solid nucleus with 
minimum grain size 
 
 
embryos 
Grain growth: 
Crystals with critical radius for 
continuous growth 
and stable of embryos 
NOTE: 
For crystal nucleation, a suitable minimum size, called a "critical 
radius", is required for continuous and stable growth during 
solidification. 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 Microstructure: 
• The mold is designed so that the solidification advances towards the 
top of the part; 
• avoiding solidification in the metal supply region, near the pour 
channel. 
 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 Microstructure: 
• As a function of the direction of heat flow through the mold, the 
natural direction of solidification and grain growth of the material 
have a preferred (crystallographic) direction from the edge to the 
center of the molding directed solidification. 
grãos com direção de crescimento cristalográfico perpendicular ao fluxo de 
calor, têm crescimento mais dinâmico 
direção de 
crescimento 
direção do fluxo de 
calor 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
As a consequence, it can develop an anisotropic microstructure during 
solidification, with different morphologies resulting from this 
process: 
* Coated or equiaxial zone: region of small grains of the same size, 
next to the wall of the mold; 
* Columnar zone: region of elongated grains, oriented according to 
the direction of heat extraction by the mold, located in the 
intermediate position between the wall and the center of the mold; 
* Central equiaxial zone: region of small grains in the center of the 
mold, resulting from the nucleation of the last part to be solidified 
and fragments of columnar grains entrained to this region of the 
mold. 
 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 
 
microestrutura interna típica de uma peça, em 
corte transversal 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
The homogeneity of the granulation and the grain size of the melt can be 
controlled by: 
* high casting temperature: coarser granulation of the material 
* pre-heating of the mold: lower cooling speed promotes smaller 
number of cores and formation of solid crystals gros coarse granulation 
* type of mold: metallic or shell favor a higher speed of cooling 
* post-cast heat treatment: standardization or refining of grain 
 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
The homogeneity of the granulation and the grain size of the melt can 
be controlled by: 
* Mechanical treatment during solidification: mold vibration or 
turbulence in casting 
* Presence of impurities or inoculants in the liquid phase: pre-
nucleus of new grain growth 
Liquid metal leakage temperature is defined by the temperature: 
* maximum: limited by mold wear 
* minimum: limited by the capacity of the metal to completely fill the 
mold, as it influences the viscosity of the material; the metal in an 
unsuitable viscosity can generate complete non-filling of the mold, 
producing the part with faults or discontinuities 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
Phenomenon that occurs during the solidification of a metallic alloy. 
• Due to the difference in solubility of certain alloying elements and / 
or impurities between the liquid and solidified metal, a non-uniform 
chemical distribution or distribution along the cast during 
solidification results in a micro or macro segregation . 
• Some of these elements / impurities can be segregated in the inter 
dendritic spaces, inside the grains or in the last part of the melt to 
solidify; 
• In the case of steels, carbon, sulfur and phosphorus are elements 
that will be distributed differently between the liquid metal and the 
solid. 
Chemical Segregation 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
• In this way, the chemical segregation favors a chemical composition 
difference between the initially solidified metal and the final one, 
resulting in a heterogeneity and chemical anisotropy throughout the 
part, with consequent influence on the mechanical (mechanical) and 
chemical properties (resistance to corrosion or oxidation ) of the 
melt. 
 
 
Chemical Segregation 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
• In order to minimize and / or eliminate the chemical 
segregation of the part, it is possible to prepare the metal with 
minimum impurities, zonal remelting, use of feeders, subsequent 
heat treatments of homogenization. 
Discontinuities: 
• If the gases and oxides formed during the casting and 
solidification are trapped in the material, the melt will exhibit 
nonmetallic porosities and inclusions, discontinuities that 
influence its properties and performance in service. 
Chemical Segregation 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
• During the solidification inside the mold, phenomena occur associated 
with the transformation of phase and cooling of the melt to the 
ambient temperature, which are associated to the volume contraction 
of the part: 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
Contraction of Solidification 
This volumetric variation of the metal during solidification and cooling is 
due to the sum of the contractions: 
* Liquid: corresponds to the lowering of the temperature of the liquid 
metal until the beginning of its solidification 
* Solidification: corresponds to the change from the liquid state to the 
solid 
* Solid: corresponds to the cooling from the end-of-solidification 
temperature to room temperature 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
Contraction of Solidification 
(a) SHRINKAGE: 
• Appearance of a void (also called sucking, retraction void or 
crater) in the cast, due to the volumetric contraction of the liquid 
metal remaining during its solidification; 
• its position in the cast depends on the location of the last region 
to solidify, at the micro or macro level. 
Consequences of contractions of the material inside the mold: 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 
 
Contração de solidificação 
Rechupe: mecanismo de ocorrência 
Solidificação x Transferência de calor x Contração 
molde 
troca de 
 calor metal / molde 
direção de 
contração 
direção de 
 solidificação 
vazio de 
contração 
sólido 
Líquido = ponto quente 
Consequences of contractions of the material inside the mold: 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 
 
Consequences of contractions of the material inside the mold: 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
SHRINKAGE 
Consequences of contractions of the material inside the mold: 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
SHRINKAGE 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
Consequences of contractions of the material inside the mold: 
SHRINKAGE 
To avoid the presence of riser in the part, one can use 
preventive or corrective solutions: Riser or "hot head" 
• the place of reserve of liquid metal inside or outside the mold, which 
is continuously made available to the interior or place of the part 
during its solidification; 
• must be positioned so as to finally solidify to fulfill its purpose of 
directing or disciplining the development of the solidification of the 
metal within the temporary mold, to compensate for the contraction 
of solidification and / or presence of the reject/shrinkage / void in 
the part; 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
• this mold element does not eliminate the chipping but causes it to be 
outside the useful part or ingot, ie in the feeder, which is 
subsequently separated from the part after demolding. 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
The leakage channel may also function as a feeder. 
• Depending on the size or geometry of the part, you can use 1 or 
more feeders in the mold. 
NOTE: Other secondary functions of the feeder channel: avoid segregation 
inside the cast, view the fill level of the mold, allow gas or debris to escape 
from the inside of the mold, fix clamps to handle the part after cooling. 
SOLIDIFICATION NUCLEARING AND DEVELOPMENTDirected solidification 
* Methods of model design and molding so as to control the 
direction of solidification in a mold or a specific region of the part, 
avoiding or minimizing the problems that volumetric shrinkage may 
cause in the melt: 
* Design of the part in order to allow a progressive cooling 
throughout the piece, through the regularization of the thicknesses, 
* Mass parts or replacing them with other forms of lower mass 
concentration 
 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
peça, com 
formas 
originais 
formas 
modificadas 
para espessuras 
razoavelmente 
iguais 
Directed Solidification 
• It is desirable that the regions of the melt furthest from the 
liquid metal supply in the pouring channel first cool and the 
solidification advance of these regions towards the feeder 
properly positioned in the mold. 
 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
* Pouring temperature: the liquid metal must be at a temperature 
and viscosity sufficient to fill the entire mold 
* Leakage under pressure: the liquid metal is pressed into the die 
until its final solidification through the die casting channel, which 
acts as feeder. 
* “Pasty phase”:This is due to the fact that the metal is in a 
"pasty" phase, that is, in a semi-solid state, it avoids the liquid 
contraction and part of the solidification contraction, minimizing the 
occurrence of chemical separation and segregation. 
massa menor 
massa maior 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
* Dimensional loss of the cast: variation in part dimensions; this 
problem can be solved by using an overmolded model / mold 
(increased dimensions) to compensate for solid contraction in 
cooling. 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
• The direction of solidification and the reactions in the solid state 
are factors causing the appearance of internal thermal 
stresses in the castings. 
• The differentiated contractions in a casting during its 
solidification and cooling may be due to the temperature gradient 
in the part, 
• Due to geometry and unequal thicknesses, favoring unequal cooling 
rates, inducing the appearance of localized or generalized 
thermal stresses. 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 
Numerical Simulation 
Software SolidCast 
 
“ ... o domínio do software de simulação 
não dispensa o conhecimento e a 
experiência do projetista, fundidor e 
engenheiro, mas soma informações 
de detalhes para tomadas de 
decisões seguras e rápidas” 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 
 
Numerical Simulation 
Software SolidCast 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 
Numerical Simulation 
Software SolidCast 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
 
Numerical Simulation 
Software SolidCast 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
Thermal stresses can cause: 
* Residual stresses  Thermal Yield Stresses plastic 
deformation 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
COMPLEMENTARY OPERATIONS IN FOUNDRY 
Paints and coatings: applied on the internal surfaces of molds and cores to 
improve the surface finish of the pieces, modify the surface structure of the 
sand or prevent the appearance of superficial defects in the castings. 
Notes: 
* increase the surface hardness of the mold in sand to prevent its erosion by 
the movement of the molten metal 
* prevent mold sand from adhering to the surface of the part 
* to modify superficially the chemical or structural nature of the casting: 
graphitizing inks to increase the carbon content, paints based on Ti, Al, Te or 
Zn to influence the initial nucleation process 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
COMPLEMENTARY OPERATIONS IN FOUNDRY 
* demoulding: in permanent or temporary molds, in addition to the exit 
angles, mold release agents are used to prevent the mold from being gripped 
on the mold walls, in the mold release; in the permanent molds, extractor 
pins in the body of the half mold, facilitate the removal of the mold part 
after cooling. 
* Cleaning and Deburring: After demolding, the part is cleaned to remove 
leaking, feeding and burring channels, by thermal cutting (oxyfuel, graphite) 
or mechanical means (cutting discs, hammers). 
In sand casting, males and sand adhered to the part, can be removed by high 
pressure water jet, with or without sand or abrasive. The surface finish can 
be done with emery, sand or shot blasting, by tumbling or other special 
media 
SOLIDIFICATION NUCLEARING AND DEVELOPMENT 
The Foundry processes present different ways and operational 
characteristics that enable several situations for the production of parts or 
semiproducts. 
 
AS TO THE TYPE OF FOUNDRY 
 
(a) Part-by-piece casting: The cast is produced from a single mold 
becoming occupied until the solidification and total cooling of the cast 
 
(b) Continuous casting of products or semi-products: the casting is 
produced continuously through a mold 
CLASSIFICATION OF FOUNDRY PROCESSES 
Casting in 
Sand 
Moulding 
Casting in 
Shell 
Moulding 
Carbon 
Dioxide 
Foundry 
Casting in 
plaster 
Lost Wax 
Casting 
Mold Casting Die Casting Centrifugal 
casting 
Continuous 
casting 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
Casting in Sand Moulding 
* Temporary mold: composed of natural sand + natural binder of 
bentonite type + H2O + drying, being the compression molding + 
cold cure to give support and integrity to compacted sand; is 
recyclable. 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
NOTE: Types of sand 
 
* Face: used to cover the model and make contact with the molten metal 
* Filling: Used to complete the molding box 
* Additives: carbon, silica powder, cellulose, sawdust, silicones → to impart 
or improve sand properties, such as plasticity, wettability, density, 
compactability, permeability, etc. 
Casting in Sand Moulding 
CLASSIFICATION OF FOUNDRY PROCESSES 
Temporary mold: consisting of sand + synthetic resin binder, molding by 
depositing and compacting the sand on a metal model plate + hot cure at 150-
350°C or cold. 
The molding generates a thin shell of 5 to 10 mm thickness, obtaining halves or 
parts of the mold, which are glued together to produce the mold itself. 
Synthetic resins: reversible / thermoplastic and irreversible / thermostable 
resinous materials, cold curing (furanic, phenolic) or heat curing (thermosetting) + 
sand 
Shell Moulding or Coring 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
 
 
 
 
 
molde montado 
para 
vazamento 
(esquemático) 
aquecimento 
casca 
Shell Moulding or Coring 
CLASSIFICATION OF FOUNDRY PROCESSES 
 CO2 
CO2 
CO2 
CO2 
areia + silicato 
de sódio 
Temporary mold: consisting of sand + synthetic sodium silicate binder, 
sand molding + gassing + curing 
Curing occurs by passing a stream of gas through the sand mold: reaction of 
CO2 with sodium silicate, forming silica gel, sodium carbonate and water, 
resulting in the cold curing of the mold rapidly. The CO 2 gassing can be 
with individual hose or tubes distributed in perforations predetermined in 
the mold or in chamber, with gas current. 
Carbon Dioxide Foundry 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
 
Mold: consisting of sand + cement cement + H2O, sand molding 
Casting in Ceramic Mold or Gypsum ("Shaw" process) 
Temporary mold: consisting of ceramic slab or refractory paste, 
being molded by filling on the model, solidifying and giving precision 
to the cast 
CLASSIFICATION OF FOUNDRY PROCESSES 
Casting in Sand-Cement or Casting in Shaw 
Temporary mold: consisting of rubber for making the wax model and 
refractory paste to obtain the casting mold itself. 
 The molding is done by the complete wrapping of the consumable wax 
model, invested by the refractory material, the wax model being melt 
removed without destroying or damaging the healedmold. 
Accuracy due to high shape / detail reproduction and dimensional 
accuracy of the model; investment because it describes the overlaying 
operation of the model with the molding mixture, called the investment 
model. 
Lost Wax Casting or Investment Casting 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
 
 
 
 
 
moldagem 
em cera 
acabamento 
da peça para 
retirada 
de canais 
vaza
mento 
do 
metal 
aquecimento do molde para 
cura da massa e derretimento 
dos modelos de cera 
preparação do 
molde para 
investimento, com 
massa refratária 
fixação dos 
modelos 
de cera 
desmoldagem 
 
 
canal de vazamento 
peça 
mesa rotativa 
canais 
canal de 
vazamento 
molde 
rotativo 
peça 
temporary or permanent mold: metallic or in sand bark subjected to 
rotation; the liquid metal is cast in the center of the rotating mold: use 
of centrifugal force for stationary or continuous mold filling 
CLASSIFICATION OF FOUNDRY PROCESSES 
Centrifugal Casting 
 
 
Die Casting 
permanent mold: cold chamber metal matrix and hot chamber to which the 
liquid metal is pressed; applicable to metals and low melting alloys, associated 
with thin and / or detailed sections / thicknesses. 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
model being 
vaporized 
during metal 
casting 
Mould Casting or Die Casting 
Temporary mold: made from a fusible or flammable model 
(styrofoam-polystyrene), which is inside the mold; during casting, 
the model melts or vaporizes under the action of the heat of the 
metal. 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
Lingotamento direto 
panela 
lingoteira 
 
Lingotamento indireto 
lingoteira 
canal de vazamento 
Conventional Casting 
permanent mold: metallic in cast iron or bronze, called "ingot"; the 
liquid metal is directly (above) or indirectly (by the base). 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
 
Continuous 
casting with 
curved mold 
 
Continuous 
casting 
with straight 
mold 
Continuous casting 
permanent mold: metallic, straight or 
curved; the continuous casting is done 
according to the number of "shafts" in the 
liquid metal distribution pan in the molds; 
several steps of a typical sequence of 
conventional casting are avoided when using 
this technique, besides producing products 
with varied sections (round, square, 
rectangular, etc.), without using mechanical 
conformation and heating of ingots for 
plastic deformation. 
CLASSIFICATION OF FOUNDRY PROCESSES 
 
molde 
metal fundido 
detalhe 
sistema de vazamento rotativo 
 
fita fundida 
Centrifugal Continuous Casting 
Permanent mold: metal; the metal is continuously injected into the mold by 
centrifugation; suitable for protective or wear resistant coatings, 
manufacture of seamless metal ribbons, restorative filler for worn surfaces, 
etc. 
CLASSIFICATION OF FOUNDRY PROCESSES 
”When you wish up stars, your dreams true” 
 by Gomes, A. P.