JP6375636B2 - Carbide tool substrate and carbide tool, and carbide tool substrate and method of manufacturing carbide tool - Google Patents

Description

  The present invention relates to a substrate for cemented carbide tool, a cemented carbide tool, and a manufacturing method thereof.

  Conventionally, cemented carbide tools using cemented carbide as a base material are known. The cemented carbide is produced by sintering metal carbide powder. As a cemented carbide having particularly excellent mechanical properties, a WC-Co based cemented carbide having tungsten carbide (WC) and cobalt (Co) as main components is known. Further, a cemented carbide tool in which a protective film is formed on the surface of a cemented carbide base material by physical vapor deposition or chemical vapor deposition to improve wear resistance and lubricity is known.

  Carbide tools are used for processing high hardness materials. The high hardness material is, for example, a high alloy pipe such as a martensitic stainless steel pipe, an austenitic stainless steel pipe, or a duplex stainless steel pipe. The carbide tool is, for example, a chaser used for thread cutting of these pipes, a plug used for drawing, a tip used for cutting, or the like.

  Japanese Laid-Open Patent Publication No. 2002-210525 discloses a cemented carbide characterized in that it is manufactured from a cemented carbide obtained by sintering WC powder with Co and the product is subjected to a surface treatment by nitriding or soft nitriding. A tool is disclosed. According to this patent document, the cemented carbide obtained by sintering WC and Co contains a small amount of impurities (Fe, Mo, etc.) in addition to WC and Co. Therefore, when nitriding or soft nitriding is performed on the cemented carbide, the impurity component is nitrided. This patent document describes that the wear resistance and fatigue strength of a cemented carbide tool can be improved by nitriding or soft nitriding.

Japanese Patent Laid-Open No. 2002-210525

In the cemented carbide tool described in the above patent document, impurities (Fe, Mo, etc.) contained in the cemented carbide are nitrided, and a nitrogen diffusion layer containing iron nitride etc. is formed on the surface layer of the cemented carbide. The The linear thermal expansion coefficient of the nitrogen diffusion layer is about 8.5 × 10 ⁻⁶ / K, and the difference from the linear thermal expansion coefficient (about 5.5 × 10 ⁻⁶ / K) of the cemented carbide is relatively large. . Therefore, a strong compressive stress exists in this nitrogen diffusion layer. Therefore, with this carbide tool, there is a concern about interfacial peeling or destruction of the entire nitrogen diffusion layer due to chipping of the nitrogen diffusion layer.

  The objective of this invention is providing the base material for carbide tools which can be strengthened.

  A method for manufacturing a substrate for a carbide tool according to an embodiment of the present invention includes a step of mixing a metal carbide powder including a tungsten carbide powder, a cobalt powder, and at least one of a titanium powder and an aluminum powder to obtain a mixture; And sintering the mixture. The total of titanium powder and aluminum powder is 3.0 to 7.0 parts by mass with respect to 100 parts by mass in total of metal carbide powder and cobalt powder.

  A method of manufacturing a cemented carbide tool according to an embodiment of the present invention includes a step of mixing a metal carbide powder including a tungsten carbide powder, a cobalt powder, and at least one of a titanium powder and an aluminum powder to obtain a mixture, A step of sintering to obtain a carbide tool substrate, and a step of heating the carbide tool substrate in a nitrogen atmosphere to form a nitrogen diffusion layer on the surface of the carbide tool substrate. The total of titanium powder and aluminum powder is 3.0 to 7.0 parts by mass with respect to 100 parts by mass in total of metal carbide powder and cobalt powder.

  The base material for carbide tools by one Embodiment of this invention is equipped with the metal carbide containing tungsten carbide, metal cobalt, at least one of metal titanium and metal aluminum. The total of metal titanium and metal aluminum is 3.0 to 7.0 parts by mass with respect to a total of 100 parts by mass of metal carbide and metal cobalt.

  The carbide tool by one Embodiment of this invention is equipped with said base material for carbide tools. The base material for carbide tools includes a nitrogen diffusion layer formed on the surface layer thereof.

  According to the present invention, a cemented carbide tool capable of increasing strength can be obtained.

FIG. 1 is a cross-sectional view schematically showing the configuration of the surface of the cemented carbide tool according to the first embodiment of the present invention. FIG. 2 is a flowchart showing an example of a method for manufacturing a cemented carbide tool. FIG. 3 is a sectional view schematically showing the configuration of the surface of the cemented carbide tool according to the second embodiment of the present invention. FIG. 4 is a flowchart showing an example of a method for manufacturing a cemented carbide tool.

  The inventor has studied a method for improving the performance of a cemented carbide tool. More specifically, a method for obtaining a high-strength cemented carbide tool was studied by applying a nitriding treatment that is inexpensive and excellent in productivity to a cemented carbide containing tungsten carbide and cobalt as main raw materials.

  Nitriding is a technique widely used as a method for increasing the strength of the surface of a steel material. However, in order to perform the nitriding treatment, it is necessary that the material to be treated contains an element having a high covalent bond with nitrogen. Cemented carbides mainly composed of tungsten carbide and cobalt are poor in elements having high covalent bonding with nitrogen. Therefore, the effect of the nitriding treatment on the cemented carbide is limited.

  The present inventor has found metal titanium and metal aluminum as elements that enable nitriding treatment. That is, the present inventor has obtained a cemented carbide tool base material that can be strengthened by nitriding treatment by adding appropriate amounts of titanium metal and aluminum metal to tungsten carbide, cobalt, etc., which are raw materials of cemented carbide. I found out that

  The inventor nitridizes a carbide tool substrate containing metal titanium and metal aluminum, or forms a protective film on the nitrided carbide tool substrate, thereby increasing the strength. The present inventors have found that a high carbide tool can be obtained and completed the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[First Embodiment]
FIG. 1 is a cross-sectional view schematically showing the configuration of the surface of the carbide tool 1 according to the first embodiment of the present invention. The cemented carbide tool 1 includes a cemented carbide tool substrate 10. A nitrogen diffusion layer 10 a is formed on the surface layer of the carbide tool base material 10.

  The base material 10 for carbide tools contains metal carbide, metal cobalt, and at least one of metal titanium and metal aluminum. As will be described later, the cemented carbide tool substrate 10 is obtained by nitriding a sintered body obtained by mixing and sintering these raw material powders.

  The metal carbide includes tungsten carbide. The metal carbide may further contain titanium carbide, tantalum carbide and the like in addition to tungsten carbide.

  The mass ratio of the metal carbide and cobalt in the base material 10 for carbide tools is, for example, 95: 5 to 80:20. If the amount of cobalt is too small relative to the amount of metal carbide, the metal carbide cannot be sufficiently bonded, so that the strength of the base material 10 for cemented carbide tool is lowered. On the other hand, if the amount of cobalt is too large relative to the amount of metal carbide, the hardness of the base material 10 for cemented carbide tool decreases. The mass ratio of metal carbide to cobalt is more preferably 92: 8 to 85:15.

  The base material 10 for carbide tools contains at least one of titanium and aluminum as a metal component in addition to cobalt. Here, “containing as a metal component” means excluding those existing as compounds. For example, when titanium carbide is included as a metal carbide, titanium element in titanium carbide is not included in titanium as a metal component.

  Titanium and aluminum have high covalent bonding with nitrogen. Titanium and aluminum exist as stable compounds after being formed as titanium nitride and aluminum nitride, and function as high-hardness crystal grains. Therefore, if the base material 10 for carbide tools containing titanium and / or aluminum is nitrided, a nitrogen diffusion layer having high hardness can be obtained. If at least one of titanium and aluminum is contained, a nitrogen diffusion layer having high hardness can be obtained by nitriding treatment.

  Moreover, if aluminum nitride is formed in the base material 10 for cemented carbide tools, the thermal conductivity of the base material 10 for cemented carbide tools will increase. Therefore, when the base material 10 for cemented carbide tools is used as the cemented carbide tool 1, the heat dissipation of the cemented carbide tool 1 increases. The carbide tool substrate 10 may contain at least one of titanium and aluminum as a metal component in order to obtain a nitrogen diffusion layer having high hardness. However, for the reasons described above, the substrate 10 contains aluminum as a metal component. More preferably.

  The total content of titanium and aluminum in the base material 10 for cemented carbide tool is 3.0 to 7.0 parts by mass with respect to 100 parts by mass in total of the metal carbide and cobalt. If the contents of titanium and aluminum are too small, sufficient hardness cannot be obtained even if the base material 10 for carbide tool is subjected to nitriding treatment. On the other hand, when the contents of titanium and aluminum are too large, the surface smoothness is deteriorated, for example, the friction coefficient or the surface roughness of the base material 10 for cemented carbide tool is deteriorated, and the adhesive force is reduced. From the viewpoint of the lower limit, the total content of titanium and aluminum is preferably 3.0 parts by mass or more, and more preferably 4.0 parts by mass or more. In terms of the upper limit, 7.0 parts by mass or less is more preferable, and 6.0 parts by mass or less is more preferable.

  As will be described later, the nitrogen diffusion layer 10a is formed by nitriding the base material 10 for carbide tool. In the nitrogen diffusion layer 10a, titanium nitride and / or aluminum nitride are dispersed and deposited.

  As described above, since titanium nitride and / or aluminum nitride functions as high-hardness crystal grains, the nitrogen diffusion layer 10a in which titanium nitride and / or aluminum nitride is dispersed and deposited has high hardness. Further, the nitrogen diffusion layer 10a in which aluminum nitride is dispersed and deposited has high heat dissipation.

Further, the linear thermal expansion coefficient of the nitrogen diffusion layer 10a containing titanium nitride and / or aluminum nitride is about 6.5 × 10 ⁻⁶ / K, and the linear thermal expansion coefficient of the portion other than the nitrogen diffusion layer 10a (about 5. The difference from 5 × 10 ⁻⁶ / K) is relatively small. Therefore, the internal stress of the nitrogen diffusion layer 10a can be suppressed to a slow compressive stress.

  The thickness of the nitrogen diffusion layer 10a is, for example, 10 to 100 μm. A preferable thickness of the nitrogen diffusion layer 10a is 10 to 30 μm. If the nitrogen diffusion layer 10a is too thin, sufficient hardness cannot be obtained. On the other hand, even if the nitrogen diffusion layer 10a is formed too thick, the effect is saturated, which is not preferable from the viewpoint of production efficiency.

[Method of manufacturing carbide tool 1]
FIG. 2 is a flowchart showing an example of a method for manufacturing the cemented carbide tool 1. The manufacturing method of the cemented carbide tool 1 according to the present embodiment includes a process of manufacturing the cemented carbide tool substrate 10 (step S1) and a nitriding process of nitriding the cemented carbide tool substrate 10 (step S2). I have.

  The process (step S1) for manufacturing the carbide tool base material 10 includes a raw material mixing process (step S1-1) and a sintering process (step S1-2).

  In the raw material mixing step (step S1-1), first, metal carbide powder and cobalt powder are prepared. It mix | blends so that mass ratio of metal carbide powder and cobalt powder may be set to 95: 5-80: 20, for example. The mass ratio of the metal carbide powder to the cobalt powder is more preferably 92: 8 to 85:15.

  The metal carbide powder includes tungsten carbide powder. The metal carbide powder may further include a titanium carbide powder, a tantalum carbide powder, and the like in addition to the tungsten carbide powder.

  The average particle diameter of the metal carbide powder is, for example, an equivalent circle diameter of 0.05 to 5.0 μm. If the particle size is too small, the production efficiency of the base material 10 for a carbide tool decreases when the powder is filled in a molding die. On the other hand, if the particle size is too large, the sintered density of the base material 10 for cemented carbide tool decreases. The average particle diameter of the cobalt powder is, for example, an equivalent circle diameter of 0.5 to 1.0 μm.

  At least one of titanium powder and aluminum powder is added to the mixture of raw material powders. At this time, it mix | blends so that the sum total of titanium powder and aluminum powder may be 3.0-7.0 mass parts with respect to a total of 100 mass parts of metal carbide powder and cobalt powder. From the viewpoint of the lower limit, the total of the titanium powder and the aluminum powder is more preferably 3.0 parts by mass or more, and further preferably 4.0 parts by mass or more. In terms of the upper limit, 7.0 parts by mass or less is more preferable, and 6.0 parts by mass or less is more preferable.

  If necessary, other raw materials may be further added to the above raw material powder mixture.

  These raw material powders are thoroughly mixed. The mixing method is arbitrary and may be wet or dry.

  The sintering process (step S1-2) includes a compacting process (step S1-2-1), a preliminary sintering process (step S1-2-2), and a main sintering process (step S1-2-3). ).

  In the compacting process (step S1-2-1), the mixture of the raw material powder obtained in the raw material mixing process (step S1-1) is cold press-molded (compact molding) into a shape corresponding to the carbide tool 1. )

  In the preliminary sintering step (step S1-2-2), the molded product obtained in the compacting step (step S1-2-1) is fired in the air. The processing temperature is, for example, 900 to 1100 ° C. The processing time (holding time at the highest temperature reached) is, for example, 30 to 120 minutes.

  In the main sintering step (step S1-2-3), the fired body obtained in the preliminary sintering step (step S1-2-2) is sintered in a vacuum atmosphere. The degree of vacuum is, for example, 5.0 Pa or less. Processing temperature is 1300-1500 degreeC, for example. The processing time (holding time at the highest temperature reached) is, for example, 30 to 240 minutes.

  The base material 10 for carbide tools is manufactured by the above process.

  In the nitriding step (step S2), the carbide tool base material 10 obtained in step S1 is heated in a nitrogen atmosphere to form the nitrogen diffusion layer 10a. More specifically, the sintered body is heat-treated in a nitrogen gas atmosphere or an ammonia gas atmosphere. The processing temperature is, for example, 450 to 600 ° C. The treatment time (holding time at the highest temperature reached) is 30 to 120 minutes.

  By nitriding the base material 10 for carbide tools containing titanium and / or aluminum, titanium nitride and / or aluminum nitride is dispersed and deposited. Titanium nitride and / or aluminum nitride exists as a stable compound and functions effectively as high-hardness grains.

  If the treatment time is too short, titanium nitride and / or aluminum nitride does not sufficiently precipitate, and the effect of improving the hardness cannot be obtained. On the other hand, even if the treatment time is excessively long, the effect is saturated, which is not preferable from the viewpoint of production efficiency.

  In the above, the structure and manufacturing method of the cemented carbide tool 1 were demonstrated. According to this embodiment, the base material 10 for carbide tools that can be increased in strength by nitriding is obtained. Moreover, the cemented carbide tool 1 obtained by nitriding the substrate 10 for cemented carbide tool has excellent strength.

  Titanium nitride and aluminum nitride have higher hardness than iron nitride or the like. Therefore, the cemented carbide tool 1 having the nitrogen diffusion layer 10a in which titanium nitride and / or aluminum nitride is dispersed and deposited has excellent surface hardness. More specifically, the carbide tool 1 has a surface hardness of Vickers hardness 2000 or more.

  In the cemented carbide tool 1 according to the present embodiment, the difference in thermal expansion coefficient between the nitrogen diffusion layer 10a and the portion other than the nitrogen diffusion layer 10a is relatively small. Therefore, chipping of the nitrogen diffusion layer 10a is suppressed. Therefore, the cemented carbide tool 1 is particularly excellent in abrasive wear resistance.

[Second Embodiment]
FIG. 3 is a cross-sectional view schematically showing the configuration of the surface of the cemented carbide tool 2 according to the second embodiment of the present invention. The cemented carbide tool 1 includes a cemented carbide tool substrate 10 and a protective film 20 formed on the nitrogen diffusion layer 10 a of the cemented carbide tool substrate 10.

  The protective film 20 includes a protective film 21, a protective film 22, and a protective film 23. The protective film 21, the protective film 22, and the protective film 23 are formed in this order from the surface of the base material 10 for carbide tools.

  Each of the protective film 21, the protective film 22, and the protective film 23 is made of any one of metal nitride, metal oxide, and metal carbide. The protective film 21, the protective film 22, and the protective film 23 enhance the wear resistance and lubricity of the carbide tool base material 10.

  Examples of the metal nitride include titanium nitride (TiN), aluminum nitride (AlN), niobium nitride (NbN), chromium nitride (CrN), and composite metal nitrides thereof (TiAlN, TiSiN, CrSiN, AlCrSiN, etc.).

Examples of the metal oxide include aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), magnesium oxide (MgO), titanium oxide (TiO), and composite metal oxides thereof.

  Examples of the metal carbide include titanium carbide (TiC), silicon carbide (SiC), titanium carbonitride (TiCN), aluminum carbonitride (AlCN), and composite metal carbonitrides thereof.

The protective film 20 preferably uses TiCN as the protective film 21, Al ₂ O ₃ as the protective film 22, and a TiN film as the protective film 23.

  The thickness of the protective film 21, the protective film 22, and the protective film 23 is, for example, 0.1 to 20 μm, respectively, and the total thickness of the protective film 20 is, for example, 1 to 40 μm.

  In the present embodiment, the case where the protective film 20 includes three layers of the protective film 21, the protective film 22, and the protective film 23 has been described. However, the protective film 20 may be composed of one layer or two layers, or may be composed of four or more layers.

[Method of manufacturing cemented carbide tool 2]
FIG. 4 is a flowchart showing an example of a method for manufacturing the cemented carbide tool 2. The manufacturing method of the cemented carbide tool 2 by this embodiment is equipped with the process (step S1) which manufactures the base material for carbide tools, a nitriding process process (step S2), and a protective film formation process (step S3). Yes. Since the process (step S1) and the nitriding process (step S2) for manufacturing the carbide tool base material are the same as those in the first embodiment, the description thereof is omitted.

  In the protective film forming step (step S3), the protective film 21, the protective film 22, and the protective film 23 are sequentially formed on the nitrogen diffusion layer 10a formed by the nitriding process (step S2). Each of the protective film 21, the protective film 22, and the protective film 23 is formed by, for example, a dry film forming method such as a physical vapor deposition method or a chemical vapor deposition method. Each of the protective film 21, the protective film 22, and the protective film 23 may be formed by different film formation methods. The protective film 21, the protective film 22, and the protective film 23 are preferably formed by a chemical vapor deposition method that is inexpensive and excellent in productivity.

  When the protective film 21 is formed by chemical vapor deposition, it is preferable that the nitriding process (step S2) and the protective film forming process (step S3) are continuously performed in the same reaction furnace. That is, it is preferable to form the protective film 21 without lowering the temperature to room temperature after the nitriding treatment. Thereby, when forming the protective film 21, it is not necessary to reheat the base material 10 for carbide tools, so that the production efficiency can be increased. More preferably, the protective film 21, the protective film 22, and the protective film 23 are all formed by a chemical vapor deposition method, and these are all performed in the same reactor. Thereby, the production efficiency can be further increased.

  In the above, the structure and manufacturing method of the cemented carbide tool 2 were demonstrated. According to the present embodiment, the cemented carbide tool 2 with improved wear resistance and lubricity than the cemented carbide tool 1 is obtained by the protective film 20.

In the carbide tool 2, the protective film 20 is formed on the nitride diffusion layer 10a. The linear thermal expansion coefficient of the protective film 20 is about 7.0 to 9.0 × 10 ⁻⁶ / K, and the linear thermal expansion coefficient (about 5.5 × 10 ⁻⁶ / K of the base material 10 for cemented carbide tool). Bigger than). On the other hand, the linear thermal expansion coefficient of the nitrided diffusion layer 10a is about 6.5 × 10 ⁻⁶ / K. Therefore, by forming the protective film 20 on the nitrogen diffusion layer 10a, compared with the case where the protective film 20 is formed on the base material 10 for carbide tool that has not been nitrided, the difference in thermal expansion coefficient is reduced. Can be small. Thereby, the adhesive force of the base material 10 for carbide tools and the protective film 20 can be improved. Therefore, the cemented carbide tool 2 is particularly excellent in abrasive wear resistance.

  Hereinafter, based on an Example, this invention is demonstrated more concretely. In addition, this Example does not limit this invention.

  A plurality of carbide tool base materials were manufactured by changing the contents of titanium powder and aluminum powder. Each carbide tool base material was nitrided to produce a carbide tool. The Vickers hardness of the manufactured cemented carbide tool was measured. Further, a protective film was formed on the nitrogen diffusion layer of each cemented carbide tool by chemical vapor deposition. The coefficient of friction and surface roughness of the cemented carbide tool on which the protective film was formed were measured, and the adhesion between the cemented carbide tool substrate and the protective film was measured.

[Manufacture of carbide tool base materials]
Tungsten carbide powder, titanium carbide powder, tantalum carbide powder, and cobalt powder were weighed to a mass ratio of 85: 3: 2: 10. Furthermore, with respect to a total of 100 parts by mass of the tungsten carbide powder, the titanium carbide powder, the tantalum carbide powder, and the cobalt powder, the titanium powder and the aluminum powder were changed in the range of 0.0 to 5.0 parts by mass, respectively. These raw material powders were mixed in a dry ball mill for 12 hours.

  Each mixture of raw material powders was compacted. The molded body was fired in air at 1000 ° C. for 60 minutes. The fired sintered body was held and sintered at 1400 ° C. for 120 minutes in an atmosphere reduced to 10 Pa or less to produce a carbide tool base material.

[Manufacture of carbide tools]
Each of the manufactured base materials for cemented carbide tools was subjected to nitriding treatment in which heat treatment was performed in a nitrogen or ammonia gas atmosphere at 500 to 550 ° C. for 60 minutes to manufacture cemented carbide tools.

[Hardness measurement]
The Vickers hardness Hv of each manufactured carbide tool was measured. The test load was 1.0 kgf. The target was to have a Vickers hardness Hv of 2000 or more.

  [Formation of protective film]

A TiCN film, an Al ₂ O ₃ film, and a TiN film were formed by chemical vapor deposition on each of the manufactured carbide tools in order from the surface of the substrate for the carbide tool.

[Friction coefficient measurement]
Each friction coefficient μ of the cemented carbide tool on which the protective film was formed was measured. Specifically, the measurement was performed by sliding a high carbon chrome steel bearing material having a diameter of 5 mm at a load of 5 N, a room temperature, a speed of 4 mm / sec, for example, a steel ball made of SUJ2, using a Bowden type sliding tester. The target was to have a friction coefficient μ of 0.30 or less.

[Surface roughness measurement]
Each surface roughness Ra of the cemented carbide tool on which the protective film was formed was measured. Specifically, Mitutoyo, SurfScan; SV-600 type is used, and an arbitrary surface after forming the protective film is scanned with a stylus (diamond needle, outer diameter 25 μm) with a length of 10 mm, and is defined in JIS B0601-1994. Arithmetic average roughness Ra was measured. The target was a surface roughness Ra of 0.40 or less.

[Adhesion measurement]
Each adhesion force F (N) of the cemented carbide tool on which the protective film was formed was measured. Specifically, using a CSEM REVESTEST type scratch tester, a diamond needle having an outer diameter of 0.2 mm and a tip angle of 120 ° is scanned at a scanning speed of 10 mm / min, a load speed of 100 N / min, and a maximum load of 105 N. The load value at the time when the ground was exposed (determined by an optical microscope) or when the tip needle detected abnormal mechanical vibration (AE signal) was defined as the adhesion force. The goal was to have an adhesion of 100 N or more.

[Measurement result]
The measurement results are shown in Table 1.

  In the columns of “Ti”, “Al”, and “Ti + Al” in Table 1, titanium powder, aluminum powder, and these powders are added to 100 parts by mass of tungsten carbide powder, titanium carbide powder, tantalum carbide powder, and cobalt powder. Total parts by mass are listed. In the “Hardness” column, the value of Vickers hardness Hv measured by hardness measurement is described. In the “friction coefficient” column, the value of the friction coefficient μ measured by the friction coefficient measurement is described. In the “surface roughness” column, the value of the surface roughness Ra measured by the surface roughness measurement is described. In the “contact force” column, the value of the contact force F (N) measured by the contact force measurement is described.

  Referring to Table 1, in the carbide tools of numbers 4 to 8, the total of titanium powder and aluminum powder is 3 with respect to 100 parts by mass of tungsten carbide powder, titanium carbide powder, tantalum carbide powder, and cobalt powder. The range was 0.0 to 7.0 parts by mass. Therefore, the carbide tools of numbers 4 to 8 had a Vickers hardness of 2000 or more. Furthermore, the carbide tools numbered 4 to 8 had a friction coefficient of 0.30 or less, a surface roughness of 0.4 or less, and an adhesion force of 100 N or more.

  In the cemented carbide tools of Nos. 1 to 3, the total amount of titanium powder and aluminum powder was less than 3.0 parts by mass with respect to 100 parts by mass in total of tungsten carbide powder, titanium carbide powder, tantalum carbide powder, and cobalt powder. It was. Therefore, the carbide tools of Nos. 1 to 3 had a Vickers hardness of less than 2000.

  In the carbide tools of numbers 9 to 11, the total of titanium powder and aluminum powder exceeded 7.0 parts by mass with respect to 100 parts by mass in total of tungsten carbide powder, titanium carbide powder, tantalum carbide powder, and cobalt powder. . Therefore, the carbide tools of numbers 9 to 11 had a friction coefficient exceeding 0.3, a surface roughness exceeding 0.4, and an adhesion force of less than 100N.

Claims (3)

Metal carbides including tungsten carbide;
Metallic cobalt,
Comprising at least one of metal titanium and metal aluminum,
The base material for carbide tools whose total of the said metal titanium and the said metal aluminum is 3.0-7.0 mass parts with respect to a total of 100 mass parts of the said metal carbide and the said metal cobalt. The substrate for a carbide tool according to claim 1 ,
The carbide tool base material is a carbide tool including a nitrogen diffusion layer formed on a surface layer thereof. The carbide tool according to claim 2 , further comprising:
A carbide tool comprising a protective film formed on the nitrogen diffusion layer and made of one or more selected from the group consisting of metal nitride, metal oxide, and metal carbonitride.

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