Engineering Materials
A small percentage of boron is added to steel in order to

Reduce machinability
Increase wear resistance
Increase hardenability
Increase endurance strength

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Engineering Materials
Y-alloy contains

5 to 6% tin, 2 to 3% copper and rest aluminium
4 to 4.5% magnesium, 3 to 4% copper and rest aluminium
3.5 to 4.5% copper, 0.4 to 0.7% magnesium, 0.4 to 0.7% manganese and rest aluminium
3.5 to 4.5% copper, 1.2 to 1.7% manganese, 1.8 to 2.3% nickel, 0.6% each of silicon, magnesium and iron, and rest aluminium

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Engineering Materials
Cobalt in steel

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

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