Abstract ALZ 309 is a high-silicon, austenitic stainless steel combining high resistance to oxidation with high tensile and creep strength at elevated temperatures. Corrosion resistance is excellent. The steel has good ductility and is readily welded so that difficult shapes and structures are easily fabricated. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: SS-820. Producer or source: ALZ nv.