Abstract AISI Type M3 is a high-carbon, high-vanadium, molybdenum-type of high-speed steel. Its composition provides marked improvement in abrasion resistance, when compared with the other standard high-speed steels. It is especially well suited for difficult cutting applications where severe abrasion exists. It is produced in two slightly different analyses: Class 1 and Class 2; Class 2 contains slightly higher percentages of carbon and vanadium and is slightly more abrasion resistant than Class 1. Among the many applications for Type M3 are broaches, milling cutters and reamers. This datasheet provides information on composition, physical properties, and hardness. It also includes information on forming, heat treating, and machining. Filing Code: TS-369. Producer or source: Tool steel mills.