3. Malleable is a ductile form of cast iron
that is produced by heat treating white
iron.
Malleable iron has moderate strength
and significantly greater ductility than
gray iron.
4. White iron is reheated ( 1700oF)(925ºC) for several hours in the
presence of materials containing oxygen, such as iron oxide.
At the elevated temperatures cementite (Fe3C) decomposes into
ferrite and free carbon.
At cooling, the combined carbon further decomposes to small
compact particles of graphite. Free carbon that released is referred to
temper carbon, the process called malleableizing.
5.
6. Moderate strength
High ductility
Machinability
Castability
Good toughness
7. Machine Construction
paper, printing and agricultural industries,
where the material is used to make oil, cooling
and lubrication pipes
Transport Industry
used for cylinder blocks and heads as well as gearbox cases. The
material is particularly effective for producing large scale parts in
commercial vehicles.
8. Heating, Cooling and Safety Systems
•used in emergency systems, such as gas and sprinkler fire
extinguishing mechanisms.
• also used in cooling, air conditioning and heating systems in
both private and commercial properties.
Gas Industry
used as the narrow threads in the material allow
pipes to be precisely aligned and sealed,
reducing the cost of construction and the
possibility of dangerous gas leakage.
9.
10. Advantages:
Excellent machinability
Significant ductility
Good shock resistance properties
Disadvantages:
The major disadvantage is shrinkage. Malleable cast
iron decreases in volume during solidification, and as
a result, requires attached reservoirs (feeders and
risers) of liquid metal to offset the shrinkage and
prevent the formation of internal or external
shrinkage defects.
