TiCN-base cermet and cutting tool and method for manufacturing cut article using the same

Abstract

A TiCN base cermet, which comprises 5 to 30 mass % of a binding phase comprising a binding metal of Co and / or Ni and hard particles bound by the binding metal, wherein a part of the hard particles comprise a core-containing structure particles composed of a core part containing TiCN and a peripheral part, and the core-containing structure particles comprise first core-containing structure particles having a peripheral part containing the binding metal and second core-containing structure particles having a core part and a peripheral part both containing the binding metal. The TiCN base cermet exhibits excellent resistance to thermal shock and to partial loss.

Description

technical field [0001] The present invention relates to a TiCN-based cermet having toughness and hardness suitable for cutting tool members, wear-resistant tool members, etc., a cutting tool using the TiCN-based cermet, and a method for manufacturing a workpiece processed by the cutting tool . Background technique [0002] Cemented carbide (WC-based sintered alloy) is used as an alloy for cutting tool components and wear-resistant tool components, but crater wear tends to occur in steel cutting, and cermets have been developed to improve it. alloy. As cermets, TiC-based cermets containing TiC as a main component have been developed, but their toughness is insufficient, and TiCN-based cermets to which TiN is added are often put into practical use. [0003] As a TiCN-based cermet, it is known that the hard particles having the most influence on its mechanical properties are double or triple core-structured particles composed of a core and a peripheral portion, thereby improv...

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Problems solved by technology

[0006] However, as described in the above-mentioned patent documents 1 and 2, the existing hard particles composed of core-structured particles have limitations in the improvement of mechanical characteristics and cutting performance, and it is particularly desirable to combine them with WC-based particles having a hard coating on the surface. Improved thermal shock resistance and wear resistance comparable to sintered alloys

[0007] In addition, as in Patent Document 3, even if there are a plurality of core-structured particles having different core / peripheral compositions, since the hard particles as the core-structured particles are composed only of carbonitrides of hard metals, Therefore, the heat conduction of cermets is poor, and the heat generated on the cutting edge cannot be efficiently released. As a result, the temperature of the cutting edge rises, and there are problems such as a decrease in thermal shock resistance and chipping resistance.

[0008] In addition, as in Patent Document 4, in the method of dispersing and distributing ultrafine alloy particles of bonding metal in hard particles, although the sinterability of the cermet is improved, the bonding metal with low hardness exists as particles, and the original bonding phase If the content ratio of metal is small, the bonding force is low, so the strength of the sintered body is reduced. In addition, the bonded metal particles may become the cause of chipping and chipping.

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