AISI Type M42 is capable of being heat treated to Rockwell C 68-70; in fact, it is a super high-speed steel. Its combination of composition and properties makes it suitable for machining high-hardness alloys and difficult-to-machine superalloys. Excellent wear resistance and high hot hardness are obtained in Type M42 without loss of cuttting-edge toughness. Typical tools made from this steel are broaches, drills, gear cutters and milling cutters. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, and machining. Filing Code: TS-476. Producer or source: Tool steel mills.