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EP-4397779-B1 - CEMENTED CARBIDE AND TOOL CONTAINING SAME

EP4397779B1EP 4397779 B1EP4397779 B1EP 4397779B1EP-4397779-B1

Inventors

  • KIDO, Yasuki
  • KIMURA, YOSHIHIRO
  • PASEUTH, ANONGSACK

Dates

Publication Date
20260506
Application Date
20221118

Claims (5)

  1. A cemented carbide consisting of a first hard phase, a second hard phase and a binder phase, wherein the first hard phase consists of tungsten carbide particles, the second hard phase consists of at least one first compound selected from the group consisting of TiNbC, TiNbN, TiNbCN, TiTaC, TiTaN and TiTaCN, the second hard phase has an average particle diameter of 0.25 µm or less as measured using the method described in the description, the second hard phase has a dispersity of more than 0.70 and 17.0 or less, a content of the first hard phase is 66 vol.% or more and 99.8 vol.% or less as measured using the method described in the description, a content of the second hard phase is 0.1 vol% or more and 15 vol% or less as measured using the method described in the description, the binder phase contains at least one first element selected from the group consisting of iron, cobalt and nickel, a content of the binder phase is 0.1 vol% or more and 19.0 vol% or less as measured using the method described in the description, the dispersity is a standard deviation of an area of each Voronoi cell in a Voronoi diagram that is obtained by performing a Voronoi partition with a center of gravity of the second hard phase as a generator, and the Voronoi diagram is obtained by extracting the second hard phases in a backscattered electron image obtained by capturing a cross section of the cemented carbide with a scanning electron microscope, setting a 12.0 µm × 8.2 µm rectangular measurement visual field in an image resulting from a binarization treatment of the backscattered electron image, performing Voronoi partitions with centers of gravity of the extracted second hard phases as generators and calculating Voronoi cells of all of the generators.
  2. The cemented carbide according to claim 1, wherein, in a 12.0 µm × 8.2 µm rectangular measurement visual field set in an image, resulting from a binarization treatment of a backscattered electron image that is obtained by capturing a cross section of the cemented carbide with a scanning electron microscope, the number of the second hard phases is 30 or more.
  3. The cemented carbide according to claim 1 or 2, wherein the second hard phase has an average particle diameter of 0.01 µm or more and 0.2 µm or less.
  4. The cemented carbide according to any one of claims 1 to 3, wherein the second hard phase has a dispersity of more than 0.70 and 15.0 or less.
  5. A tool comprising the cemented carbide according to any one of claims 1 to 4.

Description

TECHNICAL FIELD The present invention relates to a cemented carbide and a tool containing the same. BACKGROUND ART Conventionally, cemented carbides including a phase containing tungsten carbide (WC) as a main component, a phase composed of a carbide, a nitride, a carbonitride and the like containing a metallic element other than tungsten and a binder phase containing an iron group element as a main component are in use as a material for cutting tools (Patent Literature 1 to Patent Literature 9). CITATION LIST PATENT LITERATURE PTL 1: PCT International Publication No. WO 2017/191744PTL 2: Japanese Patent Laying-Open No. 2012-251242PTL 3: PCT International Publication No. 2018/194018PTL 4: Japanese Patent Laying-Open No. 2016-98393PTL 5: Japanese Patent Laying-Open No. 2021-110010PTL 6: JP S59 85860PTL 7: JP 2000 233150 APTL 8: US 2021/025038 A1PTL 9: EP 4 350 022 A1 SUMMARY OF INVENTION A cemented carbide of the present invention is a cemented carbide as defined in claim 1. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is an example of a backscattered electron image of a cemented carbide of Embodiment 1.Fig. 2 is an example of a STEM-HAADF image of the cemented carbide.Fig. 3 is an example of an element mapping image of the cemented carbide.Fig. 4 is a Voronoi diagram produced based on the backscattered electron image shown in Fig. 1.Fig. 5 is an example of a STEM-HAADF image of a cemented carbide.Fig. 6 is an example of an element mapping image of the cemented carbide.Fig. 7 is a photograph substitute showing an accretion on a cemented carbide. DETAILED DESCRIPTION [Problem to be Solved by the Present Invention] Recently, a demand for cost reduction has grown more intense, and tools having a long service life have been requested even in, for example, the processing of a heat resistant alloy. Thus, an objective of the present invention is to provide a cemented carbide enabling the extension of service lives of tools in the case of being used as tool materials and a tool containing the same. [Advantageous Effect of the Present Invention] A tool containing the cemented carbide of the present invention is capable of having a long tool service life. [Description of Embodiments] First, embodiments of the present invention will be listed and described. (1) A cemented carbide of the present invention is a cemented carbide consisting of a first hard phase, a second hard phase and a binder phase, in which the first hard phase consists of tungsten carbide particles,the second hard phase consists of at least one first compound selected from the group consisting of TiNbC, TiNbN and TiNbCN,the second hard phase has an average particle diameter of 0.25 µm or less,the second hard phase has a dispersity of more than 0.70 and 17.0 or less,a content of the first hard phase is 66 vol.% or more and 99.8 vol.% or less,a content of the second hard phase is 0.1 vol% or more and 15 vol% or less,the binder phase contains at least one first element selected from the group consisting of iron, cobalt and nickel, anda content of the binder phase is 0.1 vol% or more and 19.0 vol% or less. A tool containing the cemented carbide of the present invention is capable of having a long tool service life.(2) In the above (1), in a 12.0 µm × 8.2 µm rectangular measurement visual field set in an image after a binarization treatment of a backscattered electron image that is obtained by capturing a cross section of the cemented carbide with a scanning electron microscope, the number of the second hard phases may be 30 or more. In such a case, the adhesion resistance of the cemented carbide is improved.(3) In the above (1) or (2), the second hard phase may have an average particle diameter of 0.01 µm or more and 0.2 µm or less. In such a case, the adhesion resistance of the cemented carbide is improved.(4) In any of the above (1) to (3), the second hard phase may have a dispersity of more than 0.70 and 15.0 or less. In such a case, the adhesion resistance, heat resistance and wear resistance of the cemented carbide are improved.(5) In any of the above (1) to (4), the dispersity is a standard deviation of an area of each Voronoi cell in a Voronoi diagram that is obtained by performing a Voronoi partition with a center of gravity of the second hard phase as a generator, and the Voronoi diagram is obtained by extracting the second hard phases in a backscattered electron image obtained by capturing a cross section of the cemented carbide with a scanning electron microscope, setting a 12.0 µm × 8.2 µm rectangular measurement visual field in an image after a binarization treatment of the backscattered electron image, performing Voronoi partitions with centers of gravity of the extracted second hard phases as generators and calculating Voronoi cells of all of the generators.(6) A cemented carbide of the present invention is a cemented carbide consisting of a first hard phase, a second hard phase and a binder phase, in which the first hard phase consists of tungsten