A method for case hardening a component formed from a martensitic stainless steel material, which method comprises the steps of: forming said component from a martensitic stainless steel material having an ASTM grain size of 9 or finer; and subjecting said component to one of a carburization and a carbo-nitriding treatment, wherein: said component forming step comprises providing a martensitic stainless steel material having an ASTM grain size of at least 5 and thermo-mechanically processing said martensitic stainless steel material to have an ASTM grain size of 9 or finer, said thermo-mechanically processing step comprises subjecting said martensitic stainless steel to a first reduction of at least 50%, a second reduction of at least 60% and a third reduction of at least 70%, and each of said first, second, and third reductions is performed by forging or ring rolling at an elevated temperature using a strain rate in the range of 5.0 x 10 -1 s -1 (5.0 x 10 -1 inch/inch/second) or higher, wherein the first reduction is performed at a grain coarsening temperature of the martensitic stainless steel material, the second reduction is performed at a temperature <1010 °C (<1850 F), and the third reduction is performed at a temperature above the recrystallization temperature of the martensitic stainless steel material and below the temperature at which the second reduction is performed. forming said component from a martensitic stainless steel material having an ASTM grain size of 9 or finer; and subjecting said component to one of a carburization and a carbo-nitriding treatment, wherein: said component forming step comprises providing a martensitic stainless steel material having an ASTM grain size of at least 5 and thermo-mechanically processing said martensitic stainless steel material to have an ASTM grain size of 9 or finer, said thermo-mechanically processing step comprises subjecting said martensitic stainless steel to a first reduction of at least 50%, a second reduction of at least 60% and a third reduction of at least 70%, and each of said first, second, and third reductions is performed by forging or ring rolling at an elevated temperature using a strain rate in the range of 5.0 x 10 -1 s -1 (5.0 x 10 -1 inch/inch/second) or higher, wherein the first reduction is performed at a grain coarsening temperature of the martensitic stainless steel material, the second reduction is performed at a temperature <1010 °C (<1850 F), and the third reduction is performed at a temperature above the recrystallization temperature of the martensitic stainless steel material and below the temperature at which the second reduction is performed. said component forming step comprises providing a martensitic stainless steel material having an ASTM grain size of at least 5 and thermo-mechanically processing said martensitic stainless steel material to have an ASTM grain size of 9 or finer, said thermo-mechanically processing step comprises subjecting said martensitic stainless steel to a first reduction of at least 50%, a second reduction of at least 60% and a third reduction of at least 70%, and each of said first, second, and third reductions is performed by forging or ring rolling at an elevated temperature using a strain rate in the range of 5.0 x 10 -1 s -1 (5.0 x 10 -1 inch/inch/second) or higher, wherein the first reduction is performed at a grain coarsening temperature of the martensitic stainless steel material, the second reduction is performed at a temperature <1010 °C (<1850 F), and the third reduction is performed at a temperature above the recrystallization temperature of the martensitic stainless steel material and below the temperature at which the second reduction is performed. <EOS>