Nickle is added in large amount, over about 8%, to high chromium stainless steels to form the most important class of corrosion and heat resistance steels. These are the Austenitic s.s., typified by 18-8, where the tendency of nickel to form Austenite is responsible for a great toughness and high strength at both high & low temperatures. Nickle also improves resistance to oxidation and corrosion, it increases toughness at low temperatures when added in smaller amounts to alloy steels.
