ARMCO 22-4-9 is an austenitic stainless steel that provides high hot hardness, and retains this hardness at elevated temperatures. In addition, it has good and room and elevated temperature mechanical properties, as we as good oxidation resistance, stress rupture and creep characteristics. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-49. Producer or source: Armco Steel Corporation, Advanced Materials Division. Originally published November 1956, revised October 1970.