AISI 4820 is a low-carbon carburizing steel containing nominally 3.5% nickel and 0.25% molybdenum. It is ideal for uses that require a strong, tough core along with a highly wear-resistant carburized case. In addition, it offers a good combination of strength and low-temperature toughness for non-carburized applications. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-311. Producer or source: Alloy steel mills and foundries.