CSM 21 XL is a precipitation-hardened, high-strength stainless steel that is double melted to obtain microcleanliness for good polishability. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, joining, and surface treatment. Filing Code: SS-914. Producer or source: Crucible Materials Corporation.