CUTTING TOOL MADE OF SURFACE COVERED CEMENTED CARBIDE PROVIDING EXCELLENT RESISTANCE TO WEAR BY HARD COVERED LAYER

摘要

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface covered cemented carbide in which a hard covered layer provides excellent resistance to wear. SOLUTION: The hard covered layer in the cutting tool made of surface covered cemented carbide formed by depositing the hard covered layer having a whole average layer thickness of 12 to 25μm on a surface of a tungusten carbide group cemented carbide substrate is composed of (a) a lower part layer made of a titanium carbon nitride layer which is a highly tenacious layer having an average layer thickness of 6 to 15μm and vertically long growth crystal texture, (b) an upper part layer made of an aluminium oxide layer which has an average layer thickness of 3 to 10μm and granular crystal texture and in which a crystal structure isκtype high temperature hard layer, and (c) a surface layer formed by depositing directly on a surface of the upper part layer and made of a titanium carbide layer and/or a titanium carbon nitride layer which is a compression stress holding layer having an average layer thickness of 1.5 to 4μm and granular crystal texture. These layers are formed by depositing through an intermediate thin layer made of a titanium nitride layer which is a close adhesion layer having an average layer thickness of 0.1 to 0.6μm and granular cyrstal texture. COPYRIGHT: (C)2003,JPO