Surface Coated Cutting Tools

Abstract

The present invention provides a surface-coated cutting tool excellent in abnormal damage resistance. It forms a hard cladding layer on a tool substrate composed of a composite sintered body of TiCN-based cermet and WC-based cemented carbide, wherein (a) the surface of the TiCN-based cermet is made of WC-based cemented carbide The tool tip material forms the rake face, and forms an iron-group metal-rich layer on the surface of the tool tip material composed of WC-based cemented carbide, (b) WC-based cemented carbide on the rake face near the tool tip and In the interface part of the hard coating layer, the content of the iron group metal component of the WC-based hard alloy near the interface is 1.2 to 3.0 times the content of the iron group metal component on the inner side of the WC-based hard alloy, (c) in the TiCN-based The interface between the cermet and WC-based hard alloy forms a concentration gradient in which the content of the iron group metal decreases from the side of the TiCN-based cermet to the interface, and the content of the iron group metal component of the TiCN-based cermet near the interface is equal to that of the WC-based hard alloy. 0.1 to 0.7 times the iron group metal content on the inner side of the alloy.

Description

technical field [0001] The present invention relates to a surface-coated cutting tool (hereinafter referred to as "coated tool") excellent in abnormal damage resistance, which uses a composite sintered body of TiCN-based cermet and WC-based cemented carbide as a tool base. Background technique [0002] WC-based cemented carbide is widely used as tools for cutting steel or cast iron, but various proposals have been made conventionally in order to reduce the amount of tungsten used as a rare metal and obtain desired cutting performance. [0003] For example, in Patent Document 1, it is proposed to make a cutting edge portion with cemented carbide, and it is detachably fitted with a multi-edged insert supported on a base metal of cemented carbide, and it is described that the unit price and the cost of reducing the cutting edge are realized according to this structure. The content of the resource. [0004] Also, for example, Patent Document 2 proposes a cutting tool in which a...

AI Technical Summary

Problems solved by technology

[0009] As shown in the aforementioned Patent Documents 1 and 2, the amount of tungsten used can be reduced in cutting tools with detachable cutting edges. When used under low conditions, the fitting strength is insufficient, so sufficient cutting characteristics cannot be obtained, and due to insufficient toughness, there is a problem that the base metal will be broken from the hole part if it is used repeatedly

[0010] In addition, in the composite sintered body composed of cemented carbide and cermet layer disclosed in Patent Document 3, it is necessary not only to form irregularities at the boundary between the cemented carbide and the cermet layer, but also to obtain a composite sintered body with less deformation during sintering. The sintered body needs to have the shrinkage characteristics of the stamping body during sintering between different types of materials. Therefore, in the cutting tools made of this composite sintered body, the reduction of tungsten consumption stays at about 30% at most, which not only saves resources It cannot be fully satisfied, and there is a possibility that the cemented carbide at the tip of the tool may be destroyed by the expansion of cracks under cutting conditions such as wet interrupted cutting and other intense heat history, so it cannot be said that it has sufficient reliability.

Images