SAE 4820 is a low-carbon (nominally 0.20%) carburizing steel containing nominally 3.5% nickel and 0.25% molybdenum. It is deal for used 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. It is recommended for a wide range of moderately heavy-duty applications. Among its many uses are carburized gears, carburized aerospace components and non-carburized machinery parts. 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-409. Producer or source: Alloy steel mills and foundries.