Alloy Construction Steels
During the last fifty years, engineers have demanded steels with higher and higher tensile strength, together with adequate ductility. This has been particularly so where lightness is desirable, as in the automobile and aircraft industries. The principal alloying elements added to steel in widely varying amounts either singly or in complex mixtures are nickel, chromium, manganese, molybdenum, vanadium, silicon and cobalt. In regard to alloying elements, these steels are known as low-alloyed steels and alloyed steels. These steels are used as case hardening steels, quenched & tempered steels, free-cutting steels, nitriding steels, surface hardening steels, spring steels and high-strength steels. Alloyed steels contain carbon and a higher amount of alloying elements such as nickel, chromium, manganese, cobalt, niobium and vanadium. These elements are added to improve mechanical properties, ductility and other steel service properties.