Surface-coated cutting tool

Abstract

A surface-coated cutting tool which has excellent chipping resistance and wearing resistance in high-speed cutting processing such as high-speed gear cutting processing, high-speed milling processing,and high-speed drilling processing. The surface-coated cutting tool comprises a tool base, e.g., a cemented carbide base, cermet base, or high-speed tool steel base, and at least a hard coating layerformed on a surface of the tool base and having a multilayer structure composed of a thin layer (A) and a thin layer (B) alternating therewith. The thin layer (A) is constituted of an (Al,Cr,Si)N layer satisfying the empirical formula ¢AlXCrYSiZ!N (wherein 0.2 <= X <= 0.45, 0.4 <= Y <= 0.75, 0.01 <=Z <= 0.2, and X+Y+Z=1 in terms of atomic ratio), and the thin layer (B) is constituted of an (Al,Ti,Si)N layer satisfying the empirical formula ¢AlUTiVSiW!N (wherein 0.05 <= U <= 0.75, 0.15 <= V <= 0.94, 0.01 <= W <= 0.1, and U+V+W=1 in terms of atomic ratio).

Description

technical field [0001] The present invention relates to a hard coating layer having excellent high-temperature hardness, high-temperature toughness, high-temperature strength, and thermoplastic deformation resistance, even when used for example in high-speed gear cutting processing, high-speed milling processing, high-speed drilling processing, etc. accompanied by high heat generation. A surface-coated cutting tool (hereinafter, called a coated tool). Background technique [0002] Generally, indexable inserts, drills or micro drills, end mills, solid hobs, gear shaper cutters, and the like are known as coated tools. Indexable inserts are freely mounted on the top of the turning tool for turning or planing of various steel or cast iron workpieces; drills or micro drills are used for drilling and cutting of the above-mentioned workpieces; Milling cutters are used for plane milling, groove processing or step processing of the above-mentioned workpieces; integral hobs and gear...

AI Technical Summary

Problems solved by technology

[0010] (a) The Al component in the (Al, Cr, Si)N layer constituting the hard coating layer of the above-mentioned conventional coated tool (refer to Patent Document 1) has an effect of increasing the high-temperature hardness, and the (Al, Cr, Si)N The Cr component in the layer has the effect of improving high-temperature toughness and high-temperature strength, and at the same time has the effect of improving high-temperature oxidation resistance in a state where Al and Cr coexist, and the Si component in the (Al, Cr, Si)N layer has The role of improving thermoplastic deformation resistance, but under severe cutting conditions such as high-speed gear cutting, high-speed milling, high-speed drilling, etc. , Insufficient high-temperature strength, so it is easy to cause chipping, breakage, etc. On the contrary, even if the content of Cr is increased to improve high-temperature toughness and high-temperature strength, the wear resistance is deteriorated due to the relative reduction of the Al content , so there are limitations in the suppression and improvement of chipping resistance and fracture resistance of the hard coating layer including (Al, Cr, Si)N layers.

[0011] (b) On the other hand, the Al component and the Si component in the (Al, Ti, Si)N layer constituting the hard coating layer of the above-mentioned conventional coated tool (refer to Patent Document 2) have the same effect as above, and, The Ti component has the effect of further improving high-temperature toughness and high-temperature strength. Therefore, even under severe cutting conditions such as the above-mentioned high-speed gear cutting, high-speed milling, and high-speed drilling, the hardness of the above-mentioned (Al, Ti, Si) N layer The coating layer also exhibits excellent chipping resistance and fracture resistance, but on the other hand, it has poor wear resistance due to insufficient high-temperature hardness and thermoplastic deformation resistance.

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