Engineering Materials
Ductile cast iron

Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable
Is produced by annealing process. It is soft, tough and easily machined metal
Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material

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Engineering Materials
Chromium in steel

Improves cutting ability and reduces hardenability
Improves wear resistance, cutting ability and toughness
Gives ductility, toughness, tensile strength and anti-corrosion properties
Refines grain size and produces less tendency to carburisation, improves corrosion and heat resistant properties

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