CPM REX 20 is the second in a family of super high-speed steels made without cobalt. (For the first one, see CPM REX 25, Alloy Digest TS-365, July 1980.) CPM REX 20 is comparable to the AISI Type 40 series of high-speed steels, particularly AISI Type 42, in heat-treating response and tool performance. CPM REX 20 is designed for use in machining operations requiring heavy cuts, high speeds and feeds, and for difficult-to-machine materials that are high in hardness and abrasion resistance. Typical applications are boring tools, drills, gear cutters and punches. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on forming, heat treating, and machining. Filing Code: TS-398. Producer or source: Crucible Specialty Metals Division, Colt Industries.