View Sample Alloy Digest Data Sheet (PDF)Since 1952, Alloy Digest has been the leading reference for materials property data on metals and alloys used throughout the world. Featuring graphs, charts and tables, these sheets give facts and figures on composition or characterization, physical and mechanical properties, heat treatment, and machinability.REX AA is the original 18-4-1 high-speed steel, having been first introduced in the early 1990s. Melting practice and processing have been improved since that time, but nevertheless it is so properly balanced and the fundamental characteristics so sound, that today it is still a standard, general-purpose high-speed steel. REX AA has a wide hardening range. This steel is less susceptible to soft skin during hardening than other types and has good red hardness and toughness. Among its many applications are boring tools, broaches, cutters, drills, gear cutters, lathe tools and woodworking knives.