cemented carbides are made by compressing various metal powders (Figure F-26)and sintering (heating to weld particles together without melting them)the briquettes.Cobalt powder is used as a binder for the carbide powder used,either tungsten,titanium,or tantalum carbide powder or a combination of these. Increasing the toughness of the tool material and at the same time reduces its hardness or wear resistance. carbides have greater hardness at both high and low temperatures than do high-speed steel or cast alloys. At temperatures of 1400°F (760°C)and higher,carbides maintain the hardness required for efficient machining. This makes possible machining speeds of approximately 400 fpm in steels. The addition of tantalum increases the red hardness of tool mater.Cemented carbides are extremely hard tool materials(above RA 90),have a high compressive strenght and resist wear and rupture