Types Application Characteristics

1. CAST IRON
PRESENTED BY-
OMKAR MAGAR 1018
SANAY KHADIWALA 1039
SAAD ATAR 1047

3. CAST IRONS
Grey CI
Ductile CI
White CI
Malleable CI
Alloy CI
Good castability  C > 2.4%
Malleabilize
Stress concentration
at flake tips avoided

5. Gray Cast Iron
• Gray cast iron is characterized by its graphitic microstructure, which
causes fractures of the material to have a gray appearance.
• It is the most commonly used cast iron and the most widely use cast
material base on weight.
• Most cast irons have a chemical composition of 2.5 to 4.0% carbon, 1
to 3% silicon, and the remainder is iron.
• Gray cast iron has less tensile strength and shock resistance than
steel.
• Its compressive strength is comparable to low and medium carbon
steel.

6. Gray Cast Iron
• A low cost material that can be used for many purposes

7. Characteristics:
1) Gray Iron basically is an alloy of carbon and silicon with iron.
2) It is readily cast into a desired shape in a sand mould.
3) It contains 2.5-3.8% C, 1.1-2.8%Si, 0.4-1%Mn, 0.15% P and 0.10% S.
4) It is marked by the presence of flakes of graphite in a matrix of ferrite,
pearlite and austenite.
5) Graphite flakes occupy about 10% of the metal volume
6) Length of flakes may vary from 0.05 mm to 0.1 mm
7) When fractured, a bar of Gray Cast Iron gives gray appearance

8. Malleable Cast Iron
Malleable iron: dark graphite rosettes (temper carbon)
in an –ferrite matrix

9. Malleable Cast Iron
• Malleable iron starts as a white iron casting, that is then heat treated at
about 900 °C (1,650 °F).
• Graphite separates out much more slowly in this case, so that surface
tension has time to form it into spheroidal particles rather than flakes.
• Due to their lower aspect ratio, spheroids are relatively short and far from
one another, and have a lower cross section vis-a-vis a propagating
crack.
• They also have blunt boundaries, as opposed to flakes, which alleviates
the stress concentration problems faced by grey cast iron.
• In general, the properties of malleable cast iron are more like mild steel

10. Characteristics:
1) M.C.I. is one which can be hammered and rolled to obtain different
shapes.
2) M.C.I. is obtained from the hard and brittle white iron through a
controlled heat conversion process.
3) (i) A ferritic M.C.I. has Ferrite matrix
(ii) A pearlitic M.C.I. has pearlite matrix
(iii) An alloy M.C.I. contains chromium and nickel and possess high
strength and low corrosion resistance.
4) M.C.I. possess high yield strength.
5) High young’s modulus and low coefficient of Thermal expansion.

11. Application
1) Machine tools and structures (bed, frame and details)
2) Gas or water pipes for underground purpose
3) Manhole covers
4) Cylinder blocks and heads for I.C. engines
5) Tunnel segments
6) Frames for electric motors
7) Ingot moulds
8) Sanitary Wares
9) Piston Rings

12. Malleable Iron
Ferritic Matrix
Pearlitic Matrix
Fully Malleabilized Iron
 Complete Ferritizing Anneal
10 m
Partially Malleabilized Iron
 Incomplete Ferritizing Anneal
Pearlite (grey)
Graphite (black)
Ferrite (White)
Ferrite (White)
Graphite (black)

13. Application
1) Automotive Industry
2) Rail Road
3) Agricultural implements
4) Electrical line Hardware
5) Conveyor chain links
6) Gear case
7) Universal joint yoke
8) Rear axle banjo housing
9) Automotive crankshaft.

14. Spheroidal Cast Iron
Nodular (ductile) iron: the dark graphite nodules are
surrounded by an -ferrite matrix.

15. Spheroidal Cast Iron
• Nodular or ductile cast iron. Tiny amounts of magnesium or cerium
added to these alloys slow down the growth of graphite precipitates by
bonding to the edges of the graphite planes.
• Along with careful control of other elements and timing, this allows the
carbon to separate as spheroidal particles as the material solidifies.
• The properties are similar to malleable iron, but parts can be cast with
larger sections.

16. Characteristics:
1) Unlike long flakes as in G.S.I., graphite appears as rounded particles,
or nodules or spheroids in N.C.I.
2) The spherodizing element when added to melt eliminate sulphur and
oxygen (From the melt), which change solidification characteristics and
possibly account for the nodulization.
3) Ductile cast iron possesses very good machinablity.
4) Soft annealed grades of S.C.I. can be turned at very high feeds and
speeds.
5) The properties of S.C.I. depend upon the metal composition and the
cooling rate.
6) Spheroidal or Nodular or Ductile C.I. contains 3.2%-4.2% C, 1.1%-3.5%
Si, 0.3% - 0.8% Mn, 0.08% P and 0.2% S.
7) It possesses excellent damping capacity, casteblity and wear
resistance.

17. Mechanical Properties of SG Iron

18. Application
1) Paper industries machinery
2) I. C. engines
3) Power transmissions equipment
4) Farm implements and tractors
5) Earth moving machinery
6) Valves and fittings
7) Steel mills rolls and mill equipment
8) Pipes
9) Pumps and compressors

19. White Cast iron
White iron: the light cementite regions are surrounded by
pearlite, which has the ferrite–cementite layered structure.

20. White cast iron
• With a lower silicon content and faster cooling, the carbon in white
cast iron precipitates out of the melt as the metastable phase
cementite, Fe3C, rather than graphite.
• The cementite which precipitates from the melt forms as relatively
large particles, usually in a eutectic mixture, where the other phase is
austenite (which on cooling might transform to martensite).
• It is difficult to cool thick castings fast enough to solidify the melt as
white cast iron all the way through.
• However, rapid cooling can be used to solidify a shell of white cast
iron, after which the remainder cools more slowly to form a core of
grey cast iron

21. Characteristics:
1) W.C.I. derives its name from the fact that its freshly broken surface
shows a bright white fracture.
2) Unlike gray iron, W.C.I. has almost all its carbon chemically bonded
with the iron- as iron carbide, Fe3C which is very hard and brittle
constituent.
3) W.C.I. possesses excellent abrasive wear resistance.
4) W.C.I. under normal circumstances is brittle and not machinable.
5) By using a fairly low silicon content, cast iron may be made to solidify
as white iron.
6) W.C.I. casting can be made in sand moulds.
7) W.C.I. can also be made on the surface of a gray iron casting provided
the material is of special composition.

22. Application
1) For producing malleable iron casting
2) For manufacturing those component parts which require a hard
and abrasion resistant material.

23. Thank you