Cutting tool made of surface-coated cubic boron nitride-based ultra-high pressure sintered material having high peeling resistance

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool formed of a surface-coated cubic boron nitride-based ultra-high pressure sintered material having high peeling resistance during the high-speed cutting of high hard steel. SOLUTION: The cutting tool which is configured by forming a hard cover layer on the surface of the cBN-based ultra-high pressure sintered body having a content of cubit boron nitride of 50 to 85 vol.% is characterized in that: (a) the hard cover layer includes a lower layer and an upper layer each having an average layer thickness of 1.5 to 3 μm; (b) the lower layer is composed of a composite nitride layer of Ti and Al which satisfies a composition formula: [Ti<SB POS="POST">1-X< / SB>A1<SB POS="POST">X< / SB>]N (X is 0.30 to 0.60 at atom ratio); (c) the upper layer has the alternate laminate structure of a thin layer A and a thin layer B each having one layer average thickness of 0.03 to 0.3 μm, the thin layer A is formed of a composite nitride layer of Ti and Al which satisfies a composition formula: [Ti<SB POS="POST">1-X< / SB>A1<SB POS="POST">X< / SB>]N, and the thin layer B is formed of a Ti nitride (TiN) layer; and (d) the surface roughness, residual stress, and nano indentation hardness of a cover surface are set to predetermined values. COPYRIGHT: (C)2012,JPO&INPIT

Description

technical field [0001] The present invention relates to a cutting tool made of surface-coated cubic boron nitride-based ultra-high pressure sintered material (hereinafter referred to as coated cBN-based sintered tool). The hard coating layer of the cutting tool has excellent high-temperature hardness, high-temperature Strength, heat resistance, and excellent adhesion, so even when used in high-speed cutting of high-hardness steel such as alloy steel and bearing steel quenched material, it can also exhibit excellent peeling resistance, and it is also resistant to cutting for a long time. The excellent finishing surface accuracy of the workpiece can be maintained, and a hard coating layer is formed on the surface of the cutting tool base body composed of cubic crystal boron nitride-based ultra-high pressure sintered material. Background technique [0002] Generally, the following tools are known among the coated cBN-based sintered tools: an indexable insert detachably mounted ...

AI Technical Summary

Problems solved by technology

[0009] (a) Composite nitrides of Ti and Al ([Ti 1-X Al X ]N) layer has predetermined heat resistance, high-temperature hardness and high-temperature strength in the range of Al content ratio X (atomic ratio) in the range of 0.30 to 0.60, and has the wear resistance required under normal cutting conditions, but In the high-speed cutting of high-hardness steel that is accompanied by extremely high heat generation on the blade or at the same time applying intermittent or high-impact mechanical loads to the blade, due to the complex nitrides including Ti and Al ([Ti 1-X Al X The high-temperature strength of the hard coating layer of the ]N) layer is insufficient, so boundary abnormal damage occurs at the boundary portion of the blade, and therefore the precision of the finished surface of the workpiece cannot be maintained, and the service life is reached in a relatively short period of time

[0010] (b) On the other hand, the Ti nitride (TiN) layer has excellent high-temperature strength and impact strength, but due to insufficient heat resistance and high-temperature hardness, it is accompanied by a large heat generation and a large mechanical load is applied. In high-speed cutting of high-hardness steel, even if the hard coating layer consists of only a Ti nitride (TiN) layer, it does not have sufficient wear resistance.

Images