Spring steels are used for the making springs. Various types of these steel along with their composition and uses are discussed as under.
(i) Carbon-manganese spring steels. This type of steel contains C = 0.45 to 0.6, Si = 0.1 to 0.35% and Mn = 0.5 to 1.0%.These steels are quenched and tempered up to 350 BHN. They are widely used for laminated springs for railway and general purposes.
(ii) Hyper-eutectoid spring steels. This type of steel contains C = 0.9 to 1.2%, 0.3% (max) and Mn = 0.45 to 0.70%. These steels are oil quenched and tempered at low temperature. This type of steel is used for volute and helical springs.
(iii) Silicon-manganese spring steels. This type of steel contains C = 0.3 to 0.62%, Si = 1.5 to 2% and Mn = 0.6 to 1 %. These steels are hardened and tempered. This type of steel is used for the manufacturing of railway and road springs generally.