SPECIAL HS-55 is a hot-work tool and die steel of the 18-4-1 type of high-speed steel with lower carbon content for applications in which higher hardness must be maintained at elevated temperatures. It has a high degree of toughness and resistance to softening. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, machining, and joining. Filing Code: TS-225. Producer or source: Bethlehem Steel Corporation.