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1. Prepared By:
PALLAV RADIA
Asst prof.
AITS, RAJKOT.

2.  Iron with 1.7 to 4.5% carbon and 0.5 to 3% silicon
 Lower melting point and more fluid than steel (better
castability)
 Low cost material usually produced by sand casting
 A wide range of properties, depending on composition &
cooling rate
 Strength
 Hardness
 Ductility
 Thermal conductivity
 Damping capacity

3. Advantages and disadvantages of cast irons (in
comparison with steels):
Advantages :
• good castability
• good machinability
• antivibration properties
• low stress concentration
Disadvantages :
• high brittleness
• non machinable (white cast iron, chilled cast iron)
• cold brittleness

4.  White cast iron - carbides, often alloyed
 Grey cast iron - carbon as graphite
 Malleable cast iron
 S.G (Spheroidal graphite ) cast iron
Nodular cast iron
 Alloy of cast iron
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5.  Slow cooling favours the formation of graphite & low
hardness
 Rapid cooling promotes carbides with high hardness
 Thick sections cool slowly, while thin sections cool
quickly
 Sand moulds cool slowly, but metal chills can be used
to increase cooling rate & promote white iron
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6. Characteristics:
 White cast iron derives its name from the fact that its
freshly broken surface shows bright white fracture.
 When iron of proper composition cool fast enough the
free carbon will go in the combined form and give rise
to white iron casting.
 The result is a material with lots of iron carbide , Fe3C.
Iron carbide is a Extremely hard and brittle.
 Thus, white cast iron possesses excellent abrasive wear
resistance.
 White cast iron under normal circumstances is brittle
and Not easily machined

7.  White iron casting can be made in sand moulds.
 The solidification range of white iron is 2550 – 2065 f
 Shrinkage is 1/8 inch per foot
 White cast iron is first step in the production of malleable
iron casting
 Also made on surface of grey iron casing provide the
material in special composition
 The white iron contains
1.8 – 3.6 % C
0.5 – 2.0 % Si
0.2 – 0.8 % Mn
0.18 % P
0.10 % s

8. Application:
1. For producing malleable iron casting.
2. For manufacturing those component part which
required a hard and abrasion resistant material.

9. White cast iron showing Massive carbide areas (white) in fine pearlite(dark)
areas

10.  Flake graphite in a matrix of pearlite, ferrite or
martensite
 Wide range of applications
 Low ductility - elongation 0.6%
 Grey cast iron forms when
 Cooling is slow, as in heavy sections
 High silicon or carbon
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11. Mechanical properties
1. High Compressive strength
2. Low tensile strength
3. High rigidity
4. High stability
Casting properties
1. High fluidity and ability to make sound casting
2. Relative low melting temperature 1130 – 1250 C
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12. Machine ability
1. Easily machined to a good finish.
2. Forms a discontinuous chip.
Special properties
1. Self damping does not vibrate
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13. Characteristics:
 Gray iron basically is an alloy of silicon and carbon
with iron.
 It readily cast into desired shape in a sand mould.
 The white iron contains
2.5 – 3.8 % C
1.1 – 2.8 % Si
0.4 – 1.0 % Mn
0.15 % P
0.10 % s
 It posses machinability better than steel
 It has high resistance to wear.

14.  it marked by the precence of flake on grephite in
a matrix of ferrite.
 Graphite flakes occupy about 10 % of metal
volume
 Length of flake vary from 0.05 to 0.1 mm.
 It posses machinability better than steel
 It possesses high vibration damping capacity
 It has low ductility and low impact strength as
compare to steel.
 Grey cast iron solidification range 2400 -2000 f

15.  It has shrinkage 1/8 inch per foot
 It has possesses excellent casing qualities for pro-
ductile simple and complex shape

16.  machine tool structure(bed, frame and details)
 Gas or water pipe for underground purpose
 Manhole cover
 Cylinder blocks and head for I.C engine
 Brake drums, clutch plates
 Furnace parts, ingot and glass moulds
 Piston ring
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17.  Tunnel segment
 Rolling mill
 House hold application
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19.  Inoculation with Ce or Mg or both causes
graphite to form as spherulites, rather than
flakes
 Also known as Ductile or nodular graphite iron
 Far better ductility than grey cast iron
 See AS1831
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20. Characteristics:
 Unlike long flakes as in gray cast, graphite appears as
rounded particles, or nodule or spheroids in nodular cast
iron.
 Ductile cast iron possesses very good machinabilty.
 S.G cat iron contain
3.2 – 4.2 % C
1.1 – 3.5 % Si
0.3 – 0.8 % Mn
0.08 % P
0.2 % S
 Soft annealed grades of nodular cast iron can be turnes at
very high feeds and speed.

21. Characteristics:
 The spheroidizing element when added to melt
element sul-phur and oxygen which change
solidification characteristics and possibility
account for the nodulization.
 It possesses damping capacity intermediate
between cast iron and steel.
 It possesses excellent cast ability and wear
resistance
 The properties of S.G cast iron depend upon the
metal composition and cooling rate

22.  Paper industry machinery.
 Internal combustion engine.
 Power transmission equipment.
 Farm implements and tractor.
 Valve and fitting.
 Steel mill rolls and roll equipment.
 Pipes.
 Pumps and compressor.
 Construction machinary.
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23. Nodular cast iron showing grephite nodule surrounded by ferrite
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24.  Composition similar to grey cast iron except for
higher purity.
 Melt is added to inoculant in ladle.
 Magnesium as wire, ingots or pellets is added
to ladle before adding hot iron.
 Mg vapour rises through melt, removing
sulphur.
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25.  Strength higher than grey cast iron
 Ductility up to 6% as cast or 20% annealed
 Low cost
 Simple manufacturing process makes complex
shapes
 Machineability better than steel
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26.  Graphite in nodular form
 Produced by heat treatment of white cast iron
 Graphite nodules are irregular clusters
 Similar properties to ductile iron
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27.  Malleable cast iron is one which can be rolled
and hammered to obtain different shapes.
 Produced by heat treatment of hard and brittle
white cast iron.
 Malleable cast iron possesses high yield
strength.
 It has solidification range 2550 – 2065 f.
 Malleable cast iron contain
2 – 3 % C 0.15 % P
0.6 – 1.3 % Si 0.10 % S
0.2 – 0.6 % Mn
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28.  It has low to moderate cost.
 It has shrinkage of 3/16 inch per foot.
 It possesses good wear resistance.
 It possesses good vibration damping capacity.
 It has low Coefficient thermal expansion.
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29.  Similar to ductile iron
 Good shock resistance
 Good ductility
 Good machineability
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30.  Similar applications to ductile iron
 Malleable iron is better for thinner castings
 Ductile iron better for thicker castings >40mm
 Vehicle components
 Power trains, frames, suspensions and wheels, crank shaft
 Steering components, transmission and differential parts,
connecting rods
 Railway components
 Electrical line hardware
 Conveyor chain links
 Agricultural implements
 Pipe fittings AS3673
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31. Malleable cast iron showing ferrite matrix and temper carbon only
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32.  Alloying elements improve the mechanical properties of an iron,
by:
• Refining the grain size.
• Stabilising hard carbides.
• Producing cast irons with a martensitic or austenitic structure.
 1 Nickel: Graphitizing effect on cementite (tends to grey iron). Refines
grains for heavy sections – improving toughness.
 2 Chromium: Forms chromium carbide (harder than cementite). Wear
resistance. Less susceptible to cementite 'growth‘.
 3 Molybdenum: Increases hardness and toughness of thick sections.
 4 Vanadium: Increases strength and hardness. Better heat-resistance by
stabilising carbides so that they do not decompose on heating.
 5 Copper: Not much solubility but resists rusting
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