THYRODUR 2379 (AISI D2) is an air hardening, high carbon chromium die steel, well suited for long run tool and die applications. It is capable of great hardness and high resistance to abrasive wear. It is non-deforming; consistent in response to all machining, heat treating and production operations; and is somewhat corrosion resistant. This datasheet provides information on composition, hardness, and tensile properties. It also includes information on heat treating and machining. Filing Code: TS-520. Producer or source: Thyssen Specialty Steels Inc.