US Patent 8430075 Superaustenitic stainless steel and method of making and use thereof

A superaustenitic stainless steel comprises in weight %, 0.15 to 0.9% C, 0.2 to 1.3% Si, 0 to 0.45% Mn, 32.5 to 37.5% Cr, 13.5 to 17.5% Ni, 3.2 to 5.5% Mo, 0 to 2% Nb, 0 to 0.5% B, 0 to 2% Zr and 30 to 51% Fe. In a preferred embodiment, the superaustenitic stainless steel consists essentially of, in weight %, 0.5 to 0.9% C, 0.2 to 0.5% Si, 0.2 to 0.4% Mn, 33.0 to 35.0% Cr, 15.5 to 17.5% Ni, 4.0 to 4.5% Mo, 0.7 to 0.9% Nb, 0.07 to 0.13% B, 0 to 0.05% Zr and 40 to 46% Fe. The superaustenitic stainless steel is useful for valve seat inserts for internal combustion engines such as diesel or natural gas engines.