Compound sintered compact cutting tool and compound sintered compact cutting tool with coated surface

Abstract

The present invention is a compound sintered compact cutting tool (1) obtained from a compound sintered compact of a TiCN-based cermet layer (2) and a WC-based hard metal layer (3), wherein: the TiCN-based cermet layer contains, in mass%, 4-25% iron group metal components, less than 15% W, 2-15% Mo, 2-10% Nb and 0.2-2% Cr and the Co content ratio with respect to the total content of the iron group metal components Co and Ni is a mass ratio of 0.5-0.8; the WC-based hard metal layer contains, in mass%, 4-17% iron group metal components and at least 75% W and has WC as the main hard phase component; the angle formed by the cutting face (4) and the flank (5) is 90 degrees; the cutting face including the cutting edge is configured from the WC-based hard metal layer; the thickness of the WC-based hard metal layer is 0.05-0.3 times the thickness of the compound sintered compact; and the change in height from the upper end to the lower end of the flank in a cross-section that passes through the center of the cutting face of the cutting tool is such that the maximum height difference (10) is not more than 0.01 with respect to the thickness of the compound sintered compact.

Description

technical field [0001] The invention of the present application relates to a cutting tool composed of a composite sintered body of TiCN-based cermet and WC-based cemented carbide, and in particular to a cutting tool that realizes the reduction of the usage amount of rare metal, tungsten, and reduces the loss of the sintered body during sintering. A cutting tool with excellent heat cracking resistance due to deformation. [0002] This application claims priority based on Patent Application No. 2014-263582 filed in Japan on December 25, 2014 and Patent Application No. 2015-250733 filed in Japan on December 23, 2015, and the contents thereof are incorporated herein. Background technique [0003] 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. [0004] For example, Patent Document 1 proposes ...

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Problems solved by technology

[0010] In the composite sintered cutting tools as shown in the above-mentioned patent documents 1 and 2, although the amount of tungsten used can be reduced to some extent, 15% by mass or more of W and WC are required in the cermet, so that the use of tungsten The amount of reduction is not sufficient, and when this cutting tool is used for wet interrupted cutting, not only the strength and toughness are not sufficient, but also the heat cracking resistance is not sufficient, so abnormal damage such as chipping and chipping is likely to occur The problem

[0011] Furthermore, in the composite sintered body composed of cemented carbide and cermet shown in Patent Document 3, it is necessary not only to form irregularities at the boundary between the cemented carbide layer and the cermet layer, but also to obtain a sintered body with less deformation during sintering. Composite sintered body needs to make the shrinkage characteristics of sintered stamped body consistent between dissimilar materials. Therefore, in cutting tools made of this composite sintered body, the reduction of tungsten usage can only stay at about 30%. Not only is it not fully satisfactory from the point of view of saving resources, but also it cannot be said that it has sufficient reliability because it may damage the cemented carbide of the insert due to the expansion of cracks under cutting conditions such as wet interrupted cutting and other strong thermal processes.

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