Engineering Materials
Cobalt in steel

Improves cutting ability and reduce hardenability
Improves wear resistance, cutting ability and toughness
Refines grain size and produces less tendency to carburisation, improve corrosion and heat resistant proper ties
Gives ductility, toughness, tensile strength and anti corrosion property

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Engineering Materials
White cast iron

Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
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
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

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Engineering Materials
Smelting is the process of

Expelling moisture, carbon dioxide, sulphur and arsenic from the iron ore by heating in shallow kilns
All of these
Removing the impurities like clay, sand etc. from the iron ore by washing with water
Reducing the ore with carbon in the presence of a flux

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