AISI 4150 is a through hardening chromium-molybdenum medium carbon steel not subject to temper embrittlement. It is recommended for heavy duty service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-59. Producer or source: Alloy steel mills and foundries.