AISI 5155 is a low-alloy, through-hardening steel containing nominally 0.80% chromium. It is recommended for uses where medium harden-ability, moderate strength and low-to-moderate toughness are satisfactory. It is normally used in the oil quenched-and-tempered condition; however, it also may be used in the unhardened (annealed, as-rolled or normalized) condition. Its applications include gears, springs, wrenches and machine tool parts. 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: SA-365. Producer or source: Alloy steel mills and foundries.