SURFACE-COATED CUTTING TOOL HAVING HARD COATING LAYER EXCELLENT IN OXIDATION RESISTANCE AND ADHESION

摘要

PROBLEM TO BE SOLVED: To provide a coated tool where a hard coating layer has excellent oxidation resistance and adhesion and superior cutting performance is exhibited for a long term even when steel, cast iron and the like are machined at a high load cutting condition.SOLUTION: A problem is solved by that a hard coating layer: consists of a composite nitride with Ti and Si; has a value of X(=Si/(Si+Ti)) being an atom ratio of Si to (Si+Ti) along a layer thickness direction of 0.1-1.0; has a region gradually increasing from a tool base body side and existing over a thickness of 500 nm or more continuously; consists of a component system having an average composition: (SiTi)N{a=0.50-1.0, b=1.0-1.35} and existing in a composition inclined region having a maximum value of X in the region of 0.50-1.0 and a minimum value of 0.3 or less and at a surface side adjacent to the composition inclined region; and has at least an Si nitride layer having an average layer thickness of 0.5-1.5μm or a composite nitride layer with Si and Ti.