The present invention is to provide a method for manufacturing a martensite-based precipitation strengthening stainless steel, which effectively enables crystal grains to become finer by improving a solution treatment method. The method for manufacturing a martensite-based precipitation strengthening stainless steel containing 0.01 to 0.05 mass % of C, 0.2 mass % or less of Si, 0.4 mass % or less of Mn, 7.5 to 11.0 mass % of Ni, 10.5 to 14.5 mass % of Cr, 1.75 to 2.50 mass % of Mo, 0.9 to 2.0 mass % of Al, less than 0.2 mass % of Ti, and Fe and impurities as a remainder, which is provided by the present invention, includes performing a solid solution treatment at 845 to 895° C. once or more.

The present invention is to provide a method for manufacturing a martensite-based precipitation strengthening stainless steel, which effectively enables crystal grains to become finer by improving a solution treatment method. The method for manufacturing a martensite-based precipitation strengthening stainless steel containing 0.01 to 0.05 mass % of C, 0.2 mass % or less of Si, 0.4 mass % or less of Mn, 7.5 to 11.0 mass % of Ni, 10.5 to 14.5 mass % of Cr, 1.75 to 2.50 mass % of Mo, 0.9 to 2.0 mass % of Al, less than 0.2 mass % of Ti, and Fe and impurities as a remainder, which is provided by the present invention, includes performing a solid solution treatment at 845 to 895° C. once or more.

A method for producing a metallic component, The method includes the method steps of first machining (103) the component and thereafter cooling (105) the component from a first temperature down to a lower second temperature. The cooling (105) occurs after the machining (103) of the component.

A method for producing a metallic component, The method includes the method steps of first machining (103) the component and thereafter cooling (105) the component from a first temperature down to a lower second temperature. The cooling (105) occurs after the machining (103) of the component.

A martensitic stainless alloy comprising, in percent by weight (wt. %) C >0.50 to 0.60; Si 0.10 to 0.60, Mn 0.40 to 0.80; Cr 13.50 to 14.50; Ni 0 to 1.20; Mo 0.80 to 2.50; N 0.050 to 0.12; Cu 0.10 to 1.50; V max 0.10; S max 0.03; P max 0.03; the balance being Fe an unavoidable impurities.

According to the invention, a metal workpiece made by additive manufacturing is subjected, following the additive manufacturing process, to a cold treatment in which the workpiece is cooled to a lower target temperature of less than minus 30° C. in a cooling phase and is then heated up to an upper target temperature in a heating phase. The cold treatment significantly improves the properties of the workpiece in respect of the mechanical quality thereof.

According to the invention, a metal workpiece made by additive manufacturing is subjected, following the additive manufacturing process, to a cold treatment in which the workpiece is cooled to a lower target temperature of less than minus 30° C. in a cooling phase and is then heated up to an upper target temperature in a heating phase. The cold treatment significantly improves the properties of the workpiece in respect of the mechanical quality thereof.

A precipitation hardenable, martensitic stainless steel is disclosed. The alloy has the following broad composition in weight percent.

TABLE-US-00001 Ni 10.5-12.5 Co 1.0-6.0 Mo 1.0-4.0 Ti 1.5-2.0 Cr  8.5-11.5 Al Up to 0.5 Mn  1.0 max. Si 0.75 max. B 0.01 max.

The balance of the alloy is iron and the usual impurities found in commercial grades of precipitation hardenable martensitic stainless steels as known to those skilled in the state of the art in melting practice for such steels. A method of making parts from the alloy and an article of manufacture made from the alloy are also described.

A bearing component composed of a chromium-molybdenum-vanadium alloyed tool steel is produced by a process that includes: (i) performing a first preheating within a temperature range of 600-650° C., (ii) performing a second preheating within a temperature range of 850-900° C., (iii) austenitizing in vacuum at 1000-1180° C. for 20-40 min, (iv) gas quenching at a minimum of 4-5 bar overpressure, and (v) tempering by performing either a double temper at 520-560° C. for 1.5-2.5 hours in each temper, or a triple temper at 520-560° C. for 0.5-1.5 hours in each temper. The steel alloy may be composed (in mass percent) of 1.32-1.45 C, 0.32-0.50 Si, 0.26-0.48 Mn, 4.0-4.85 Cr, 3.35-3.55 Mo, 3.55-3.85 V, 0-0.13 W, 0-0.20 Ni, 0-0.15 Cu, 0-0.8 Co, 0-0.03 P, and 0-0.03 S, the balance being iron and unavoidable impurities. Mo may be replaced with W or vice versa in a replacement ratio Mo:W of 1:2.

A method of making a forged, martensitic, stainless steel alloy is provided. The alloy is a forged preform of martensitic, pitting corrosion resistant stainless steel alloy comprising, by weight: 12.0 to 16.0 percent chromium; greater than 16.0 to 20.0 percent cobalt, 6.0 to 8.0 percent molybdenum, 1.0 to 3.0 percent nickel, 0.02 to 0.04 percent carbon; and the balance iron and incidental impurities. The alloy has a microstructure that comprises a retained austenite phase less than or equal to 2 percent by volume of the microstructure. The method heats the preform to a solutionizing temperature to form a solutionized microstructure. The preform is cooled with a liquid to room temperature. The preform is immersed in a cryo-liquid to transform the retained austenite phase in the microstructure to martensite. The preform is heated to a temperature of less than 600° F. for a time sufficient to form a tempered forged preform.