SAE 1021 is a carbon steel of relatively high manganese content which increases hardenability and hardness over that of carbon steels of lower manganese. It combines good machinability, good workability (hot or cold) and good weldability. It is used in the annealed, hot-worked, normalized, cold-worked or water-quenched-and-tempered condition for many applications. It may be used in uncarburized applications and for components case-hardened by carburizing. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-64. Producer or source: Carbon steel mills.