AISI 4130 is a through-hardening chromium-molybdenum alloy steel. It is not subject to temper embrittlement. It may be nitrided. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-23. Producer or source: Alloy steel mills and foundries. Originally published November 1954, revised March 1988.