Patent ID: 7470336

Claim:
A method of producing an alloy comprising: preparing an alloy comprising (wt. %): greater than 0.05% and less than 0.15% C; greater than 7.5% and less than 15% Cr; greater than 1% and less than 7% Ni; up to about 15% Co; up to about 8% Cu; up to about 8% Mn; up to about 4% Si; up to about 6% (Mo+W); greater than 0.01% and less than 0.75% Ti; less than 0.1% N; up to about 2% Al; and at least about 40% Fe; thermal mechanically treating by austenitizing the alloy at a temperature greater than 1000° C.; hot working the alloy at a temperature greater than 1000° C. to impart a true strain of greater than about 0.20 (20%); and cooling the alloy to room temperature to obtain a fine-grained martensitic microstructure in which the ASTM grain size is greater than or equal to 5.