Cubic boron nitride sintered body cutting tool

Abstract

In a cBN sintered body cutting tool having a sintered body including cBN grains and a binder phase as the tool base body therefor, the sintered body contains at least 40 capacity% but less than 60 capacity% cBN grains, a minimum of 2% by mass of Al, and a maximum within a range that fulfils the relationship Y= -0.1X+10, when Y is the Al content ratio (capacity %) and X is the cBN content ratio (% by mass). The binder phase contains at least a Ti-based compound, Al2O3, and unavoidable impurities. Al2O3 that has a diameter of 10-100 nm, among said Al2O3, is dispersed and generated within the binder phase and at least 30 Al2O3 being generated within a 1 [mu]m * 1[mu]m cross-sectional area of the binder phase.

Description

technical field [0001] The invention of the present application relates to a cutting tool with cubic boron nitride (hereinafter represented by cBN) as the main component, and the cBN sintered body formed by sintering and molding it under ultra-high pressure and high temperature as the tool matrix, and relates to A cBN sintered body cutting tool is excellent in strength and toughness, especially in cutting high-hardness steel such as alloy steel and bearing steel, has excellent wear resistance and chipping resistance, and can maintain excellent cutting performance during long-term use. [0002] This application claims priority based on Patent Application No. 2014-069233 filed in Japan on March 28, 2014 and Patent Application No. 2015-58192 filed in Japan on March 20, 2015, and uses the contents thereof here. Background technique [0003] Conventionally, cBN sintered body cutting tools using a cBN sintered body as a tool base are known as high-hardness steel cutting tools, and...

AI Technical Summary

Problems solved by technology

[0010] Patent Document 1 discloses a cBN sintered body that contains, as an insulating phase component, a first compound selected from the group consisting of Al, Si, Ti, and one or more elements of Zr and one or more elements selected from N, C, O, and B, and have an average particle size of less than 100 nm, so that the thermal conductivity of the cBN sintered body becomes 70 W / m K or less, but in this sintered body, when the content of cBN is less than 60% by volume, sufficient cutting performance cannot be obtained, and the tool life is short.

[0011] In addition, Patent Document 2 discloses a cBN sintered body including cBN and a binder phase containing 25% by volume to 80% by volume of the cBN in the cBN sintered body, and the binder phase includes Ti-based Compound group, the Ti-based compound group includes at least one compound containing Ti, and includes a first particle component composed of particles with a particle size of 0.1 μm or less, and the first particle component is contained in at least one of the cBN sintered body One cross-section accounts for 10 to 60% of the area occupied by the binder phase, thereby achieving a high degree of both fracture resistance and wear resistance. However, in this sintered body, only the particle size of the TiN-based compound group is controlled, so there is no Can control the particle size of the combined phase components of other components, such as the formation of coarse Al 2 o 3 , AlN, AlB 2 , and with this as a starting point, cracks are likely to occur and spread, which will cause the toughness of the cBN sintered body to decrease

[0012] In addition, Patent Document 3 discloses a cBN sintered body containing a predetermined amount of W and / or Co, Si, or Zr as a binder, and TiN, TiB 2 The average particle size of AlB 2 , The average particle size of AlN is set within the specified range, thereby improving the fracture resistance and wear resistance, but it cannot be said that the sintered body has sufficient cutting conditions under the cutting conditions of high hardness steel and high load. Defect resistance

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