AISI 8742 is a chromium, nickel, molybdenum alloy steel. It is oil hardening, has good hardenability and has desirable toughness. It is recommended for tough, high strength, heavy duty applications. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-155. Producer or source: Alloy steel mills and foundries.