Cubic boron nitride sintered body and cutting tool

Abstract

A sintered body containing cubic boron nitride and a binding agent, characterized in that the binding agent comprises at least one compound selected from among nitrides, carbides, carbonitrides and borides of elements belonging to IVa, Va and VIa Groups, and a boride comprising an element belonging to IVa, Va or VIa Group and a VIII Group element. The sintered body is improved in abrasion resistance and also in the fallout of cBN particles.

Description

technical field [0001] The present invention relates to a sintered product which has high hardness and excellent wear resistance and is useful as a wear-resistant material for manufacturing cutting tools, bearings, wire drawing dies and the like. Background technique [0002] Conventionally, tungsten carbide (WC)-based superhard materials have been used as wear-resistant materials for manufacturing cutting tools and the like. However, these WC-based superhard materials have encountered difficulties in meeting users' requirements, as the requirements have become increasingly stringent. Therefore, it is desirable to develop wear-resistant materials with more superior properties. [0003] Wear-resistant materials satisfying the above requirements have been proposed. For example, a sintered product of cubic (cubic crystal) boron nitride (hereinafter abbreviated as cBN) powder is proposed, to which is added a metal phase containing a small amount of Al and at least one alloying...

AI Technical Summary

Problems solved by technology

[0005] The cBN sintered product disclosed in the above-mentioned JP-A SHO 48-17503 or JP-B SHO 57-3631 cannot achieve sufficient wear resistance during cutting of cast iron under high speed conditions

A conceivable reason for the former case is that the temperature of the cutting edge increases due to the cutting heat generated under high-speed cutting conditions, and although the heat keeps the cBN particles firmly in the sintered product, thereby contributing to the Densification, but a reaction occurs between the material to be cut and a binder formed by an alloying element such as Ni, Co, Fe, Mn or V, which is highly reactive with the material to be cut, whereby worsen wear resistance

On the contrary, in the latter case, when TiN or similar ceramics with low reactivity with the material to be cut and poor cBN particle retention ability are applied as a binder, the cBN particles tend to fall off

In addition, the content of cBN cannot be increased to a high level due to the difficulty in densification of sintered products

Therefore, sufficient wear resistance cannot be achieved