Polycrystalline cubic boron nitride blanks for cutting tool are compound super-hard material of polycrystalline cubic boron nitride layer and WC sintered under ultrahigh pressure and high temperature. It has the hardness, wear resistance and thermal stability of cubic boron nitride and the shock-resistant toughness of hard alloy. It is the ideal material of cutting processing of high-hard ferrous metals and non-ferrous metal alloy. Cubic boron nitride compact of Supreme Company has excellent performance in processing cast iron and processing work piece surface is highly polished and very durable.