EXTENDO-DIE hot work die steel combines extreme toughness with good red hardness in large section sizes. Although primarily used as a hot work tool steel, Extendo-Die may be considered for many cold work applications, particularly in large sections, where AISI H13 tool steel is used. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on heat treating and machining. Filing Code: TS-507. Producer or source: Carpenter.