The document provides an overview of engineering cast iron, detailing its definition, types, and properties. It explains the different classifications of cast iron, including gray, ductile, malleable, and white cast iron, along with their applications and advantages. Additionally, it discusses the effects of various alloying elements on the properties of cast iron.

1. ENGINEERING CAST IRON
SAYAN DAS
Roll - 001311301010
METALLURGICAL AND
MATERIAL ENGINEERING
DEPARTMENT
JADAVPUR UNIVERSITY

2. Overview of Engineering Cast Iron
Joseph Glanville wrote of cast iron, 'Iron seemeth a simple metal but
in its nature are many mysteries’. Many, but not all,of these mysteries
have been solved over the past three hundred years using the
combined skill of the foundryman and the knowledge of the scientist
to provide today's design engineer with a family of casting alloys that
offer a virtually unique combination of low cost and engineering
versatility.
The various combinations of low cost with castability , strength,
Machinability , hardness, wear resistance ,corrosion resistance,
thermal conductivity and damping are unequalled among all casting
alloys and It makes Cast Iron most widely used metal in engineering
purpose .

3. Definition
Cast Iron is generally defined as an alloy of Iron with greater than 2%
Carbon, and usually with more than 0.1% Silicon.

4. Types of Cast Iron
We can classified Cast iron in 4 major types depending on their
chemical composition of the iron, rate of cooling of the casting in the
mold (which depends on the section thickness in the casting),
types of graphite formed (if any) ~~

5. Gray Cast Iron
Gray Iron is by far the oldest and most
common form of cast iron. As a result, it
is assumed by many to be the only form
of cast iron and the terms "cast iron" and
"gray iron" are used interchangeably.
Gray Iron, named because its fracture
has a gray appearance, consists of
carbon in the form of flake graphite in a
matrix consisting of ferrite, pearlite or a
mixture of the two. The fluidity of liquid
gray iron, and its expansion during
solidification due to the formation of
graphite, have made this metal ideal for
the economical production of shrinkage-
free, intricate castings such as motor
blocks.

6. Properties of Gray Cast Iron
 Graphite morphology and matrix characteristics affect the
physical and mechanical properties of gray cast iron.
o . Large graphite flakes produce good dampening capacity,
dimensional stability, resistance to thermal shock and ease of
machining.
o While on the other hand, small flakes result in higher tensile
strength, high modulus of elasticity, resistance to crazing and
smooth machined surfaces
 Grey Cast Iron is highly resistant to rust, which is formed by the
reaction of oxygen and Iron. It is a perfect solution to avoid the
problem of corrosion.
 Grey Cast Iron has low melting point – 1140 ºC to 1200 ºC.

7. Applications of Gray Cast Iron
Gray Cast Iron Can be used in producing heavy-duty machine tools,
bed, presses, high pressure hydraulic parts, frame, gears, bushings,
piston rings, cams, crankshaft, cylinder block, cylinder head, gear,
cylinder, base, bed, flywheel, cylinder liners, pistons, brake wheel,
gear boxes, pressure valve, coupling plate etc.
pressure valve Bushings Gear

8. Applications of Gray Cast Iron
Brake Wheel Cylinder Block
Coupling Plates
Machine Tool
Hydraulic Casting Parts

9. Ductile Iron
Ductile cast iron is yet another type of ferrous alloy that is used as an
engineering material in many applications. To produce ductile iron, small
amount of magnesium is added to the molten iron, which alters the
graphite structure that is formed. The magnesium reacts with oxygen
and sulphur in the molten iron leading to nodule shaped graphite that
has earned them the name-nodular cast iron.

10. Properties of Ductile Iron
 Strength higher than grey cast iron
 Ductility up to 6% as cast or 20% annealed
 Low cost
o Simple manufacturing process makes complex shapes
 Machineability better than steel
 Ductile cast iron offers significantly low shrinkage during casting.
Applications
 Automotive industry are the major user of ductile iron castings.
o Crankshafts, front wheel spindle supports, steering knuckles,
disc brake callipers
 Water pipe and pipe fittings industry.

11. Applications
Various Automotive Industry Parts made using Ductile Iron
Ductile Pipe Pipe Fittings

12. Malleable iron
Unlike Gray and Ductile Iron, Malleable Iron
is cast as a carbidic or white iron and an
annealing or "malleablizing" heat treatment
is required to convert the carbide into
graphite. The microstructure of Malleable
Iron consists of irregularly shaped nodules of
graphite called "temper carbon" in a matrix
of ferrite and/or pearlite. The presence of
graphite in a more compact or sphere-like
form gives Malleable Iron ductility and
strength almost equal to cast, low-carbon
steel. The formation of carbide during
solidification results in the conventional
shrinkage behaviour of Malleable Iron and
the need for larger feed metal reservoirs,
causing reduced casting yield and increased
production costs.

13. Types of Malleable Iron
Depending on Annealing treatments we can get two types of
Malleable Iron –
 Ferritic Malleable Cast iron
– Depends on C and Si
– 1st stage 2 to 36 hours at
940˚C in a controlled
atmosphere
– Cool rapidly to 750˚C &
hold for 1 to 6 hours
 pearlitic malleable iron
– 1st stage 2 to 36 hours at
940˚C in a controlled
atmosphere
– Cool to 870˚C slowly, then
air cool & temper to
specification

14. Advantages
 Excellent machinability
 Significant ductility
 Good shock resistance properties
Application
Malleable cast iron is used for connecting rods and universal joint
yokes, transmission gears, differential cases and certain gears,
compressor crankshafts and hubs, flanges, pipe fittings and valve
parts for railroad, marine and other heavy-duty applications.
Marine Hardware made by Malleable Iron

15. White Cast Iron
White cast iron is unique in that it is the only
member of the cast iron family in which carbon is
present only as carbide. Due to the absence of
graphite, it has a light appearance. The presence
of different carbides, depending on the alloy
content, makes white cast irons extremely hard
and abrasion resistant but very brittle.
It has lower silicon content and low melting point. The carbon present in
the white cast iron precipitates and forms large particles that increase
the hardness of the cast iron. It is abrasive resistant as well as cost-
effective making them useful in various applications like lifter bars and
shell liners in grinding mills, wear surfaces of pumps, balls and rings of
coal pulverisers, etc.

16. Applications
Lifter Bars and Shell Liners in
Grinding MillsBearing Surface

17. Effects of Alloying Elements on Cast Iron
Cast iron's properties are changed by adding various alloying elements
 Silicon
After carbon, silicon is the most important alloyant because it forces
carbon out of solution. A low percentage of silicon allows carbon to
remain in solution forming iron carbide and the production of white
cast iron. A high percentage of silicon forces carbon out of solution
forming graphite and the production of grey cast iron.
 Sulphur
Sulphur, when present, forms iron sulphide, which prevents the
formation of graphite and increases hardness. The problem with
sulphur is that it makes molten cast iron viscous, which causes
short run defects.

18. Effects of Alloying Elements on Cast Iron
 Manganese
To counter the effects of sulphur, manganese is added because the
two form into manganese sulphide instead of iron sulphide. The
manganese sulphide is lighter than the melt so it tends to float out of
the melt and into the slag. The amount of manganese required to
neutralize sulphur is 1.7 × sulphur content + 0.3%. If more than this
amount of manganese is added, then manganese carbide forms,
which increases hardness and chilling, except in grey iron, where up
to 1% of manganese increases strength and density.
 Nickel
Nickel is one of the most common alloying elements because it
refines the pearlite and graphite structure, improves toughness, and
evens out hardness differences between section thicknesses.

19. Effects of Alloying Elements on Cast Iron
 Chromium
Chromium is added in small amounts to the ladle to reduce free
graphite, produce chill, and because it is a powerful carbide
stabilizer; nickel is often added in conjunction.
 Molybdenum
Molybdenum is added on the order of 0.3–1% to increase chill and
refine the graphite and pearlite structure; it is often added in
conjunction with nickel, copper, and chromium to form high strength
irons.
 Copper
Copper is added in the ladle or in the furnace, on the order of
0.5–2.5%, to decrease chill, refine graphite, and increase
fluidity.

20. Thank
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