ABSTRACT
Materials with good machinability require little power to remove material, achieve cutting at high speed, easily obtain a good finish, and cause tool wear. Knowing how difficult or easy it is to machine when compared to a familiar material like free-cutting steel provides the machinability rating of the material. Since there is no unit of machinability, it is usually assessed by comparing one material against another, one of which is taken as a reference. The problem associated here is that if different tool materials are used to assess relative machinability, different ratings may occur. Brief guidelines concerning the machinability of various metals and nonmetallic materials are presented. Carbon and manganese have various effects on the machinability of steels, depending on their composition. Nonconventional machining processes are established to cut more difficult-to-machine materials such as high-strength thermal-resistant alloys, carbides, fiber-reinforced composite materials, Stellites, and ceramic materials.
