Classification of cast iron

Cast Iron
Classification, Composition, Properties and Uses of Cast Iron

Introduction
Presented by:
1. Ali Ahssan Roll no. 8630
2. M. Aqib Roll no. 8607
3. Nafees Ahmad Roll no. 8642
4. M. Furqan Roll no. 8633
5. Faisal Shahzad Roll no. 8619
Presented to Engr. Adeel
Government College University Of Fasilabad (Sahiwal Sub-Campus)

Content
 Cast Iron
 Classification of the Cast Iron
 Alloy Cast Iron
 Mottled Cast Iron
 White Cast Iron
 Malleable Cast
 Ductile Cast Iron

Cast Iron
The product of the blast furnace i.e. pig
iron is unsuitable for casting as it contains
impurities in high percentage. To render it
suitable for desire purpose it is refined in
the furnace known as cupola. The refined
product is termed as cast iron.
Cast iron is a group of iron-carbon alloy
with a carbon content greater than 2%. It
is made by re-melting pig iron.
Engineering Material by R. K. Rajput

Classification of Cast Iron
Cast iron maybe classified as follows :
 Grey cast iron
 White cast iron
 Mottled cast iron
 Nodular cast iron
 Malleable cast iron
 Alloy cast iron

Alloy Cast Iron
The cast iron is supposed to be very hard,
brittle, lacking in tensile and transverse
strength and weak to withstand shocks it
is alloyed with other metals to improve its
properties. Amongst the alloying metals,
nickel is predominating alloying
constituent whose addition to the extent
of 0.5% to 1.5% avoids the tendency of
chilling or hard spots.
http://www.vertix.co/alloy-cast-iron-en/

Composition of Alloy Cast Iron
Alloy cast iron fall into two groups: those that
contain graphite and those that don’t, and
both are designated “white” irons. These are
detailed in the below table. As with steels,
any of these alloys containing oxide-forming
elements such as chromium, added to
promote corrosion resistance, give more
problems on casting, as a result of the
surface oxide formation. The high-nickel,
heat-resistant cast irons (Ni-resists),
however, are relatively easy to cast, and
certainly much easier to cast than the
equivalent heat-resistant steel alloys.

Properties of Alloy cast iron
 High operating temperatures
 Outstanding corrosion resistance
 Lightweight
 Very good strength and hardness
 Good stiffness and strength-to-weight ratio
 Excellent thermal conductivity
 High electrical conductivity
 Good finishing characteristics
 Full recyclability
https://www.reliance-foundry.com/blog/cast-iron#gref

Uses of Alloy cast Iron
 It is used in making pipes, to carry suitable fluids.
 It is used in making different machines.
 It is used in making automotive parts.
 It is used in making pots pans and utensils.
 It is used in making anchor for ships.
https://clubtechnical.com/cast-iron

Malleable Cast Iron
Malleable cast iron is essentially white
cast iron which has been modified by heat
treatment. It is formed when white cast
iron is heated to around 920 deg C and
then left to cool very slowly
https://www.ispatguru.com/malleable-cast-iron/

Composition of Malleable Cast Iron
It is obtained by giving a long time annealing to cast iron. To get the high cast irons,
steel scraps 10% to 40% maybe added to lower the total carbon contents.
The procedure of obtaining malleable cast iron is as follows:
The white cast iron casting along with silica is packed in steel pot in heated muffle
oven or continuous type thermal kiln. The temperature is maintained at 870 deg C for
60 hours and casting is cooled slowly in the furnace, iron carbide dissociates at Fe3C
Fe + C and thus reduces to malleable cast iron.

Properties of Malleable Cast Iron
Following are the properties of malleable cast iron:
 Hardness-material’s resistance to abrasion and indentation.
 Toughness-material’s ability to absorb energy.
 Ductility-material’s ability to deform without fracture.
 Elasticity-material’s ability to return to its original dimensions after it has been
deform.

Uses of Malleable Cast Iron
Following are the basic uses of malleable cast iron:
 It is used in machine construction.
 It is used in transport industry.
 It is used in heating, cooling and safety systems.
 It is used in gas industry.
https://www.reliance-foundry.com/blog/cast-iron#gref

Mottled Cast Iron
Cast iron or pig iron that is intermediate between white cast iron and grey cast iron
and shows a mottled surface on fracture is known as mottled cast iron.
Iron which consists of a mixture of a variable proportions of gray cast iron and white
cast iron, such a material has a mottled fracture.

Composition of Mottled Cast Iron
Following is the composition of mottled cast iron:
Combined Carbon 1.75%
Graphite 1.75%
Iron 93.5%
The remainder are impurities

Properties of mottled Cast Iron
 Mixture of the two states, grey cast iron and white cast iron.
 Strength and hardness varies according to the ratio of free carbon to combined
carbon.
 Less tendency to rust than grey cast iron variety.
 Fluidity is good.
 Hard and brittle.

Uses of Mottled Cast Iron
The only use of mottled cast iron is for the manufacturing of manhole’s covers and
pipes.

White Cast Iron
White cast iron is a type of carbon-iron alloy that contains carbon content greater than
2% in the form of cementite. When fractured it exhibits a silver-like (white) fracture.
White cast iron has high compressive strength and wear resistance.
https://www.corrosionpedia.com/definition/5425/white-
cast-iron

Composition of White Cast Iron
Following are the elements present in the composition of white cast iron:
 Iron 94%
 Graphite carbon 0.5%
 Combined carbon 3.5%
 And the remainder are impurities.

Properties of White Cast Iron
Following are the properties of white cast iron:
 Hard brittle and cannot be machined.
 So called because the carbon is mostly in combined form.
 Highly resistance and wear.
 Tensile strength is good.
 Obtained by rapid cooling of metal.
 Due to its poor fluidity it does not fill the mould freely.

Uses of White Cast Iron
The uses of the white cast iron are as below:
 Used for parts subjected to excessive wear, e.g. in rim of freight car wheels or
railway breaks blocks.
 Used for inferior castings and does not rust so much as grey variety.
 Used for making malleable castings also.

Ductile Cast Iron
 Ductile Iron is a type of cast iron
known for its impact and fatigue
resistance, elongation, and wear
resistance due to the spherical
graphite structures in the metal.
Ductile iron is also called ductile
cast iron.
https://Willmanind.com

Composition of Ductile Cast Iron
 Ductile cast iron contain more than 2% C.
 Ductile cast iron is the alloy of carbon with 1.7 to 4.5%
carbon and 0.5 to 3% silicon.
 Butt in some alloy it has manganese 0.5 to 1.0%
Phosporous 0.1 to 0.9% & Sulphur 0.07 to 0.10%

Properties of Ductile
Cast Iron
Ductile iron owes its remarkable mechanical properties to the spheroidal shape of its graphite:
• tensile strength,
• impact resistance,
• high elastic limit,
• good elongation.
These properties are further enhanced by control of the chemical analysis and heat treatment of the
metal matrix.
Ductile iron maintains the traditional qualities of cast irons, resulting from the high carbon content:
 compression strength,
 castability,
 abrasion resistance,
 machinability,
 fatigue strength. https://www.saint-gobain-pam.co.uk

Uses of Ductile Cast Iron
 Following are the basic uses of ductile cast iron.
 It is used in automotive application.
 It is used in vehicle components power trains, frames, suspension and wheels
,crank shaft.
 It is used in steering components, transmission and different parts connecting
rods.
 It is used in agriculture impelement, roads and construction application.

Classification of cast iron

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