SURFACE-COATED TUNGSTEN CARBIDE-BASED CEMENTED CARBIDE CUTTING TIP OBTAINED BY FORMING HARD COATING LAYER FREE OF INTERLAYER BONDED SURFACE

摘要

PURPOSE:To allow the tip to exhibit peeling resistance in cutting even under severe conditions by forming a hard coating layer free of an interlayer bonded surface on the surface of a WC-based cemented carbide substrate. CONSTITUTION:A hard coating layer is formed on the surface of a WC-based cemented carbide substrate by chemical or physical vapor deposition. In this case, a mixed structure of a Ti compd. among TiC, TiN, TiCN and TiCNO and Al2O3 at the center of the coating layer in its thickness direction, and the Al2O3 concn. in the mixed structure is gradually decreased from the substrate bonded surface toward the surface side.