THYROTHERM 2344 SUPRA ESR is a premium quality AISI H13 work tool steel with consistent and uniform properties in all directions, particularly impact value. It has the capability of attaining an optical lens quality polish. This datasheet provides information on composition, physical properties, and hardness as well as fracture toughness. It also includes information on heat treating, joining, and surface treatment. Filing Code: TS-527. Producer or source: Thyssen Specialty Steels Inc.