CRUCIBLE 17Cr-4Ni SUPER-X is a precipitation-hardening martensitic stainless steel which develops high strength and hardness after relatively simple heat treatment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-521. Producer or source: Crucible Specialty Metals Division, Colt Industries.