ALLEGHENY LUDLUM EXOHARD is an ultrahard high-speed tool steel (AISI Type M47) suited for machining hard and otherwise difficult-to-machine materials. This datasheet provides information on composition, physical properties, and hardness as well as fracture toughness. It also includes information on wear resistance as well as heat treating, machining, and joining. Filing Code: TS-234. Producer or source: Allegheny Ludlum Corporation.