HEPPENSTALL C58 is an alloy tool and die steel furnished in the prehardened and in the annealed conditions. It is used for dies where very high compressive strength and resistance to softening at elevated temperatures are required. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-213. Producer or source: Midvale-Heppenstall Company.