Allegheny Ludlum AL 17-4 Precipitation Hardening Alloy is a chromium-nickel-copper stainless steel. It maintains high strength to about 600 F (316 C) and it exhibits a moderate level of corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-497. Producer or source: Allegheny Ludlum Corporation.