LESCALLOY 4340 VAC-ARC is a low-alloy steel that can be heat treated to high strength levels. It has a good combination of strength, ductility and toughness along with high hardenability. It is produced by the vacuum-consumable-electrode process to provide optimum cleanliness and preferred ingot structure. It is used for aircraft components including retainer rings for critical bearings and other heavy-duty applications. This datasheet provides information on composition, physical properties, and elasticity. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-361. Producer or source: Latrobe Steel Company.