CIRCLE C (AISI T5) tool steel combines increased wear resistance from higher vanadium and carbon contents with higher red hardness due to 8 to 9% cobalt content. This datasheet provides information on composition and hardness as well as fracture toughness, and deformation. It also includes information on wear resistance as well as heat treating and machining. Filing Code: TS-502. Producer or source: Teledyne Vasco.