AISI 1566 is a high-carbon (nominally 0.66% carbon) steel containing 0.85-0.15% manganese. Its hardenability is low and on austenitizing and liquid quenching it develops a hard (martensitic) surface with a soft, ductile core. It can be used in the hot-rolled, annealed, normalized, cold-worked or liquid-quenched-and-tempered condition for a wide range of applications. It has good machinability and good workability. Its many uses include springs, shafts, hand tools, railway parts and agricultural machinery. 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, machining, joining, and surface treatment. Filing Code: CS-100. Producer or source: Carbon steel mills.