SURFACE COVERED TUNGSTEN CAR BIDF RDADICAL CEMENTED CARBIDE CUTTING TOOL HAVING HARD OVERLATER SUPERIOR IN INTERLAYER A ADHESION PERFORMANCE

摘要

PURPOSE: To exhibit superior cutting performance for a long time in the case of used for cutting soft steel, etc., having high cutting resistance by setting a titanium carbide nitride layer into a longitudinally oblong growth crystal structure and setting an aluminum oxide layer into a structure mainly consisting of kappa type crystal. ;CONSTITUTION: On the surface of a cemented carbide base body, a hard overlayer which is formed from the first layer consisting of TiN having a granular crystal structure, the second layer consisting of TiCN having similar granular crystal structure, the third layer consisting of TiCO or TiCNO having similar granular crystal structure, and the forth layer consisting of Al₂O₃ having alpha crystal structure is formed in prescribed mean layer thickness in the range of 3-30μm. In this occasion, the second TiCN layer is set to a longitudinally oblong growth crystal structure and the forth Al₂O₃ is set to a structure mainly consisting of kappa crystal. The interlayer adhesion performance of the hard overlayer is thus improved.;COPYRIGHT: (C)1995,JPO