Malleable Iron Malleable Iron Malleable Iron
Introduction
MALLEABLE IRON is a type of cast iron that has most of its carbon in the form of irregularly shaped graphite
nodules instead of flakes, as in gray iron, or small graphite spherulites, as in ductile iron. Malleable iron is
produced by first casting the iron as a white iron and then heat treating the white cast iron to convert the iron
carbide into the irregularly shaped nodules of graphite. This form of graphite in malleable iron is called temper
carbon because it is formed in the solid state during heat treatment.

Additional comments :

Malleable iron, like ductile iron, possesses considerable ductility and toughness because of its combination of
nodular graphite and a low-carbon metallic matrix. Consequently, malleable iron and ductile iron are suitable
for some of the same applications requiring good ductility and toughness, with the choice between malleable
and ductile iron based on economy and availability rather than properties. However, because solidification of
white iron throughout a section is essential in the production of malleable iron, ductile iron has a clear
advantage when the section is too thick to permit solidification as white iron. Malleable iron castings are
produced in section thicknesses ranging from about 1.5 to 100 mm ( 1
16
to 4 in.) and in weights from less than
0.03 to 180 kg ( 1
16
to 400 lb) or more.
Ductile iron also has clear advantages over malleable iron when low solidification shrinkage is needed. In other
applications, however, malleable iron has a distinct advantage over ductile iron. Malleable iron is preferred in
the following applications:
· Thin-section casting
· Parts that are to be pierced, coined, or cold formed
· Parts requiring maximum machinability
· Parts that must retain good impact resistance at low temperatures
· Parts requiring wear resistance (martensitic malleable iron only)
Malleable iron (and ductile iron as well) also exhibits high resistance to corrosion, excellent machinability,
good magnetic permeability, and low magnetic retention for magnetic clutches and brakes. The good fatigue
strength and damping capacity of malleable iron are also useful for long service in highly stressed parts.