0.3C-CrMoV(ESR) Steel: A New Ultrahigh Strength Steel

摘要

0.3C-CrMoV(ESR) steel is a new ultrahigh strength medium-carbon low alloy steel which is developed as a cost effective material for space applications. It is a quenched and tempered steel and upon heat treatment it develops an ultimate tensile strength (UTS) of up to 1700 MPa with a corresponding 0.2% proof strength of 1400 MPa and a tensile elongation of 8%. The steel is processed through the secondary melting practice of electro-slag refining (ESR). Inoculation with niobium is employed to reduce the grain size of the steel. ESR-cast ingots are subjected to thermo-mechanical processing like hot forging, rolling and ring-rolling to realize product forms such as plates, rings and bars. It has excellent cold and hot working characteristics, and it is amenable to welding processes such as gas tungsten arc welding and plasma arc welding. Filler wire having the same chemical composition as that of the base metal is used, and a welding efficiency close to 100% is achievable. In this paper, brief outline on the steel's characteristics such as chemical composition, processing details, mechanical properties of base metal and weld metal, etc. is provided.