Voestalpine Australia 4140 is medium-carbon, chromium-molybdenum direct hardening alloy steel that is also suitable for flame hardening, induction hardening, and nitriding. This steel is a medium hardenability steel in the 0.40 to 0.42 mean carbon content classification. In general, it is used for medium and large size parts requiring high strength and toughness. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on heat treating, machining, and joining. Filing Code: SA-873. Producer or source: voestalpine High Performance Metals.