Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B27/00—Tools for turning or boring machines; Tools of a similar kind in general; Accessories therefor
  • B23B27/14—Cutting tools of which the bits or tips or cutting inserts are of special material
  • B23B27/148—Composition of the cutting inserts
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
  • C22C29/02—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
  • C22C29/06—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds
  • C22C29/08—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds based on tungsten carbide
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/90—Carbides
  • C01B32/914—Carbides of single elements
  • C01B32/949—Tungsten or molybdenum carbides
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/05—Mixtures of metal powder with non-metallic powder
  • C22C1/051—Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F2005/001—Cutting tools, earth boring or grinding tool other than table ware
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2224/00—Materials of tools or workpieces composed of a compound including a metal
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C2200/00—Crystalline structure

Definitions

• the present disclosure relates to cemented carbide and tools containing the same.
• a cemented carbide comprising tungsten carbide particles and a binder phase containing cobalt is widely used as a material for cutting tools (Patent Document 1).
• the cemented carbide of the present disclosure is a cemented carbide comprising tungsten carbide particles and a binder phase,
• the total content of the tungsten carbide particles and the binder phase in the cemented carbide is 80% by volume or more,
• the content of the binder phase in the cemented carbide is 0.1% by volume or more and 20% by volume or less,
• a first peak exists in the class of the misorientation of 29.5° or more and less than 30.5°
• the class on the horizontal axis of the histogram indicates the orientation difference, and the width of the class is 1.0 °
• the frequency on the vertical axis of the histogram is cemented carbide indicating the ratio of the number of adjacent pairs belonging to each class to the number of all adjacent pairs in the cemented carbide.
• the tool of the present disclosure is a tool containing the above cemented carbide.
• FIG. 1 is a schematic enlarged view of a cemented carbide according to Embodiment 1.
• FIG. 2 is an example of a histogram showing the distribution of misorientation between adjacent pairs of two adjacent tungsten carbide grains in the cemented carbide according to Embodiment 1.
• FIG. 1 is a schematic enlarged view of a cemented carbide according to Embodiment 1.
• FIG. 2 is an example of a histogram showing the distribution of misorientation between adjacent pairs of two adjacent tungsten carbide grains in the cemented carbide according to Embodiment 1.
• an object of the present disclosure is to provide a cemented carbide that can extend the tool life when used as a tool material, and a tool using the same.
• a tool comprising the cemented carbide of the present disclosure can have a long tool life.
• the cemented carbide of the present disclosure is a cemented carbide containing tungsten carbide particles and a binder phase,
• the total content of the tungsten carbide particles and the binder phase in the cemented carbide is 80% by volume or more
• the content of the binder phase in the cemented carbide is 0.1% by volume or more and 20% by volume or less
• a first peak exists in the class of the misorientation of 29.5° or more and less than 30.5°
• the class on the horizontal axis of the histogram indicates the orientation difference, and the width of the class is 1.0 °
• the frequency on the vertical axis of the histogram is cemented carbide indicating the ratio of the number of adjacent pairs belonging to each class to the number of all adjacent pairs in the cemented carbide.
• a tool containing the cemented carbide of the present disclosure can have a long tool life.
• the frequency of the grade of the orientation difference of 29.5° or more and less than 30.5° is 0.010 or more and 0.2 or less.
• a tool containing the cemented carbide can suppress the propagation of cracks that accompany use of the tool. Therefore, tool life is further improved.
• the second peak exists in the class of the orientation difference of 89.5° or more and less than 90.5°. According to this, the matching between particles is good, the strength of the grain interface is high, and the strength of the cemented carbide is improved.
• the histogram is preferably created by performing EBSD analysis on the cross section of the cemented carbide and measuring the orientation difference between the adjacent pairs of all tungsten carbide grains present within a rectangular measurement field of 85 ⁇ m ⁇ 115 ⁇ m provided on the cross section.
• the tool of the present disclosure is a tool containing the cemented carbide. Tools of the present disclosure can have long tool life.
• a to B means the upper and lower limits of the range (that is, A to B or less), and if no units are described in A and only units are described in B, the unit of A and the unit of B are the same.
• the cemented carbide of one embodiment of the present disclosure (hereinafter also referred to as “this embodiment” or “embodiment 1”) is A cemented carbide comprising tungsten carbide particles and a binder phase, The total content of the tungsten carbide particles and the binder phase in the cemented carbide is 80% by volume or more, The content of the binder phase in the cemented carbide is 0.1% by volume or more and 20% by volume or less,
• a first peak exists in the class of the misorientation of 29.5° or more and less than 30.5°
• the class of the horizontal axis of the histogram indicates the orientation difference, and the width of the class is 1.0 °
• the frequency on the vertical axis of the histogram is the cemented carbide indicating the ratio of the number of adjacent pairs belonging to each class to the total number of adjacent pairs in
• a tool containing the cemented carbide of this embodiment can have a long tool life. The reason for this is presumed to be as follows (i) and (ii).
• the total content of tungsten carbide particles (hereinafter also referred to as "WC particles") and the binder phase is 80% by volume or more, and the content of the binder phase in the cemented carbide is 0.1% by volume or more and 20% by volume or less. According to this, cemented carbide can have suitable hardness and wear resistance for tools.
• the cemented carbide of Embodiment 1 includes tungsten carbide particles and a binder phase.
• the lower limit of the total content of tungsten carbide particles and binder phase is 80% by volume or more, preferably 82% by volume or more, and 84% by volume or more.
• the upper limit of the total content of tungsten carbide particles and binder phase is preferably 100% by volume or less.
• the total content of the tungsten carbide particles and the binder phase is preferably 80% by volume or more and 100% by volume or less, 82% by volume or more and 100% by volume or less, or 84% by volume or more and 100% by volume or less.
• the lower limit of the content of tungsten carbide particles in the cemented carbide can be 60% by volume or more, 62% by volume or more, 64% by volume or more, and 70% by volume or more.
• the upper limit of the content of tungsten carbide particles in the cemented carbide can be 99.9% by volume or less, 99% by volume or less, 98% by volume or less, or 95% by volume or less.
• the content of tungsten carbide particles in the cemented carbide is 60% to 99.9% by volume, 62% to 99.9% by volume, 64% to 99.9% by volume, 70% to 99.9% by volume, 60% to 99% by volume, 62% to 99% by volume, 64% to 99% by volume, 70% to 99% by volume, 60% to 98% by volume, 62% by volume.
• % or more and 98 vol% or less 64 vol% or more and 98 vol% or less, 70 vol% or more and 98 vol% or less, 60 vol% or more and 95 vol% or less, 64 vol% or more and 95 vol% or less, 70 vol% or more and 95 vol% or less.
• the binder phase content of the cemented carbide is 0.1% by volume or more and 20% by volume or less. According to this, the toughness of the cemented carbide is improved.
• the lower limit of the binder phase content of the cemented carbide can be 0.1% by volume or more, 0.5% by volume or more, 1% by volume or more, and 2% by volume or more.
• the upper limit of the binder phase content of the cemented carbide can be 20% by volume or less, 18% by volume or less, 16% by volume or less, or 14% by volume or less.
• the binder phase content of the cemented carbide is 0.1% to 20% by volume, 0.5% to 20% by volume, 1% to 20% by volume, 2% to 20% by volume, 0.1% to 18% by volume, 0.5% to 18% by volume, 1% to 18% by volume, 2% to 18% by volume, 0.1% to 16% by volume, and 0.5% to 16% by volume. 1% to 16% by volume, 2% to 16% by volume, 0.1% to 14% by volume, 0.5% to 14% by volume, 1% to 14% by volume, 2% to 14% by volume.
• the cemented carbide of Embodiment 1 preferably consists of tungsten carbide particles and a binder phase.
• the cemented carbide may contain hard phase particles other than tungsten carbide and/or impurities in addition to tungsten carbide particles and binder phase, as long as the effects of the present disclosure are not impaired.
• the hard phase particles include carbides, nitrides, carbonitrides, oxides containing at least one selected from the group consisting of titanium, niobium, tantalum, zirconium, molybdenum, chromium and vanadium, and solid solutions and composites thereof.
• the impurities include, for example, iron, molybdenum, calcium, silicon, sulfur and the like.
• Cemented carbide can consist of tungsten carbide particles, a binder phase and impurities. Cemented carbide can consist of tungsten carbide grains, binder phase and hard phase grains. Cemented carbide can consist of tungsten carbide grains, binder phase, hard phase grains and impurities.
• the cemented carbide can contain hard phase particles.
• the lower limit of the content of hard phase particles in the cemented carbide can be 0% by volume or more, 0.1% by volume or more, or 0.2% by volume or more.
• the upper limit of the content of hard phase particles in the cemented carbide can be 20% by volume or less, 18% by volume or less, or 16% by volume or less.
• the content of the hard phase particles in the cemented carbide can be 0 to 20 vol%, 0.1 to 20 vol%, 0.2 to 20 vol%, 0 to 18 vol%, 0.1 to 18 vol%, 0.2 to 18 vol%, 0 to 16 vol%, 0.1 to 16 vol%, and 0.2 to 16 vol%.
• the methods for measuring the tungsten carbide particle content, binder phase content, and hard phase particle content of cemented carbide are as follows (A1) to (H1).
• the mirror-finished surface of the cemented carbide is photographed with a scanning electron microscope (SEM) to obtain a backscattered electron image.
• the photographing area of the photographed image is set at the central part of the cemented carbide cross section, that is, at a position that does not include a part that clearly differs in properties from the bulk part such as the vicinity of the surface of the cemented carbide (the position where the entire photographing area is the bulk part of the cemented carbide).
• the observation magnification is 5000 times.
• the measurement conditions are an acceleration voltage of 3 kV, a current value of 2 nA, and a working distance (WD) of 5 mm.
• (D1) Analysis is performed on the imaging region of (C1) above using an energy dispersive X-ray analyzer (SEM-EDX) attached to the SEM, and the distribution of the elements specified in (B1) above in the imaging region is specified to obtain an elemental mapping image.
• SEM-EDX energy dispersive X-ray analyzer
• a region in which at least one element selected from the group consisting of iron, cobalt, and nickel is present in the elemental mapping image and shown in white in the binarized image corresponds to the region in which the binder phase exists.
• (G1) Set one rectangular measurement field of view of 24.9 ⁇ m ⁇ 18.8 ⁇ m in the image after the binarization process.
• the area percentage of each of the tungsten carbide particles, the binder phase and the hard phase particles is measured using the area of the entire measurement field as the denominator.
• (H1) The measurement of (G1) above is performed in five different measurement fields that do not overlap each other.
• the average area percentage of tungsten carbide particles in the five measurement fields corresponds to the tungsten carbide particle content (% by volume) of the cemented carbide
• the average area percentage of the binder phase in the five measurement fields corresponds to the binder phase content (% by volume) of the cemented carbide
• the average area percentage of the hard phase particles in the five measurement fields corresponds to the hard phase particle content (% by volume) of the cemented carbide.
• the content of impurities in the cemented carbide (if there are two or more types of impurities, the total of these contents) is preferably 0% by mass or more and less than 0.1% by mass.
• the content of impurities in cemented carbide is measured by ICP emission spectroscopy (inductively coupled plasma emission spectroscopy (measuring device: Shimadzu "ICPS-8100" (trademark)).
• WC particles are particles made of tungsten carbide.
• WC particles can contain iron (Fe), molybdenum (Mo), calcium (Ca), silicon (Si), sulfur (S), etc., as long as the effects of the present disclosure are not impaired.
• the content of iron (Fe), molybdenum (Mo), calcium (Ca), silicon (Si), and sulfur (S) in the WC particles is preferably 0% by mass or more and less than 0.1% by mass.
• the contents of iron (Fe), molybdenum (Mo), calcium (Ca), silicon (Si), and sulfur (S) in WC particles are measured by ICP emission spectrometry.
• the lower limit of the average particle diameter of the tungsten carbide particles in Embodiment 1 is preferably 0.1 ⁇ m or more, 0.2 ⁇ m or more, and 0.3 ⁇ m or more.
• the upper limit of the average particle size of the tungsten carbide particles is preferably 3.5 ⁇ m or less, 3.0 ⁇ m or less, or 2.5 ⁇ m or less.
• the average particle diameter of the tungsten carbide particles is 0.1 ⁇ m to 3.5 ⁇ m, 0.2 ⁇ m to 3.5 ⁇ m, 0.3 ⁇ m to 3.5 ⁇ m, 0.1 ⁇ m to 3.0 ⁇ m, 0.2 ⁇ m to 3.0 ⁇ m, 0.3 ⁇ m to 3.0 ⁇ m, 0.1 ⁇ m to 2.5 ⁇ m, 0.2 ⁇ m to 2.5 ⁇ m, 0.3 ⁇ m to 2.5 ⁇ m. ⁇ m or less is preferable.
• the cemented carbide has a high hardness, and the wear resistance of the tool containing the cemented carbide is improved. Also, the tool can have excellent breakage resistance.
• the average grain size of tungsten carbide grains means the D50 equivalent circle diameter (Heywood diameter) of the WC grains contained in the cemented carbide (equivalent circle diameter at which the cumulative number-based frequency is 50%, median diameter D50).
• a method for measuring the average particle diameter of the tungsten carbide particles is as follows.
• the cemented carbide of this embodiment includes a binder phase.
• the binder phase preferably contains at least one first element selected from the group consisting of iron, cobalt and nickel.
• the content of the first element in the binder phase is preferably 90% by mass or more and 100% by mass or less, 95% by mass or more and 100% by mass or less, 98% by mass or more and 100% by mass or less, or 100% by mass.
• the binder phase preferably contains cobalt as a main component.
• the binding phase containing cobalt as a main component means that the content of cobalt in the binding phase is 90% by mass or more and 100% by mass or less.
• the binder phase can contain tungsten (W), chromium (Cr), vanadium (V), titanium (Ti), niobium (Nb), tantalum (Ta), etc., in addition to the first element.
• composition of the binder phase can be measured by ICP emission spectrometry (equipment used: "ICPS-8100” (trademark) manufactured by Shimadzu Corporation).
• ⁇ Distribution of orientation difference between adjacent pairs> In the histogram showing the distribution of the misorientation between adjacent pairs of two adjacent tungsten carbide grains in the cemented carbide of Embodiment 1, a first peak exists in the class of the misorientation of 29.5° or more and less than 30.5°.
• the class on the horizontal axis of the histogram indicates the orientation difference
• the width of the class is 1.0°
• the frequency on the vertical axis of the histogram indicates the ratio of the number of adjacent pairs belonging to each class to the number of all adjacent pairs in the cemented carbide.
• FIG. 1 shows a schematic enlarged view of the cemented carbide of Embodiment 1.
• FIG. 1 shows a schematic enlarged view of the cemented carbide of Embodiment 1.
• FIG. 1 shows a schematic enlarged view of the cemented carbide of Embodiment 1.
• FIG. 1 shows a schematic enlarged view of the cemented carbide of Embodiment 1.
• FIG. 1 shows a schematic enlarged view of the cemented carbide of Embodiment 1.
• one WC grain is arbitrarily selected from a plurality of tungsten carbide grains 1 in FIG.
• a one arbitrarily selected tungsten carbide grain is denoted by symbol a.
• WC grain a there are three adjacent tungsten carbide grains indicated by symbols b, c, and d (hereinafter referred to as “WC grain b”, “WC grain c”, and “WC grain d”).
• WC particle a when WC particle a is used as a reference, there are three adjacent pairs: an adjacent pair of WC particles a and WC particles b, an adjacent pair of WC particles a and WC particles c, and an adjacent pair of WC particles a and WC particles d.
• the orientation difference between adjacent pairs is measured for each of the three adjacent pairs.
• FIG. 2 shows an example of the above histogram for the cemented carbide of Embodiment 1.
• the class on the horizontal axis indicates the misorientation between adjacent pairs of two adjacent tungsten carbide grains in the cemented carbide, and the width of the class is 1.0°.
• the classes are arranged in ascending order of orientation difference.
• the frequency on the vertical axis of the histogram indicates the ratio of the number of adjacent pairs belonging to each class to the total number of adjacent pairs in the cemented carbide.
• the numerical value on the horizontal axis of FIG. 2 indicates the lower limit of the class.
• the rod class indicated by 26.5 is a misorientation of 26.5° or more and less than 27.5°.
• the first peak indicated by symbol A exists in the class of the orientation difference of 29.5° or more and less than 30.5°.
• the presence of the first peak in the class of misorientation of 29.5° or more and less than 30.5° means that the frequency of the class of misorientation of 29.5° or more and less than 30.5° satisfies the following condition (a).
• the frequency of the class with the orientation difference of 29.5° or more and less than 30.5° is 1.2 times or more the maximum value of the frequency of the ten classes of the orientation difference of 24.5° or more and less than 29.5° and the orientation difference of 30.5° or more and less than 35.5°.
• the frequency of the grade of the orientation difference of 29.5° or more and less than 30.5° is 0.026.
• the range of the orientation difference of 24.5° or more and less than 29.5° and the ten classes of the orientation difference of 30.5° or more and less than 35.5° are the five classes within the range indicated by symbol a1 and the five classes within the range indicated by symbol a2.
• the maximum value of the frequency in these 10 classes is 0.007 in the class with a misorientation of 28.5° or more and less than 29.5°.
• the frequency of 0.026 in the class with the orientation difference of 29.5° or more and less than 30.5° is 3.7 times the maximum value of 0.007 in the above 10 classes. Therefore, the histogram shown in FIG. 2 satisfies the above condition (a).
• the lower limit of the frequency in the class of misorientation of 29.5° or more and less than 30.5° is preferably 0.010 or more, 0.011 or more, and 0.012 or more from the viewpoint of improving the effect of suppressing crack growth.
• the upper limit of the frequency in the class of the misorientation of 29.5° or more and less than 30.5° is not particularly limited, it can be, for example, 0.2 or less.
• the frequency in the class of the misorientation of 29.5° or more and less than 30.5° is preferably 0.010 or more and 0.2 or less, 0.011 or more and 0.2 or less, and 0.012 or more and 0.2 or less.
• the frequency of the class with the orientation difference of 29.5° or more and less than 30.5° is 1.2 times or more, preferably 2 times or more and 3 times or more, the maximum value of the frequency of the 10 classes.
• the second peak exists in the class of misorientation of 89.5° or more and less than 90.5°. According to this, the matching between particles is good, the strength of the grain interface is high, and the strength of the cemented carbide is improved.
• the presence of the second peak in the class of misorientation of 89.5° or more and less than 90.5° means that the frequency of the class of misorientation of 89.5° or more and less than 90.5° satisfies the following condition (b).
• the frequency of the class with the orientation difference of 89.5° or more and less than 90.5° is 1.5 times or more the maximum value of the frequency of the eight classes in the range of the orientation difference of 85.5° or more and less than 89.5° and the range of the orientation difference of 90.5° or more and less than 94.5°.
• the frequency of the grade of the orientation difference of 89.5° or more and less than 90.5° is 0.267.
• the eight classes in the range of the orientation difference of 85.5° or more and less than 89.5° and the range of the orientation difference of 90.5° or more and less than 94.5° are the four classes within the range indicated by symbol b1 and the four classes within the range indicated by symbol b2.
• the maximum value of the frequency in these eight classes is 0.094 in the class with an orientation difference of 88.5° or more and less than 89.5°.
• the frequency of 0.267 in the class with the orientation difference of 89.5° or more and less than 90.5° is 2.8 times the maximum value of 0.094 in the above eight classes. Therefore, the histogram shown in FIG. 2 satisfies the above condition (b).
• the lower limit of the frequency in the class of misorientation of 89.5° or more and less than 90.5° is preferably 0.10 or more, 0.12 or more, and 0.14 or more from the viewpoint of improving the effect of suppressing crack growth.
• the frequency in the class of the misorientation of 89.5° or more and less than 90.5° it can be, for example, 0.3 or less. It is preferable that the frequency of the grade of the misorientation of 89.5° or more and less than 90.5° is 0.10 or more and 0.3 or less, 0.12 or more and 0.3 or less, and 0.14 or more and 0.3 or less.
• the frequency of the class with the orientation difference of 89.5° or more and less than 90.5° is 1.5 times or more, preferably 1.7 times or more and 2.0 times or more, the maximum value of the frequency of the eight classes.
• the mirror-finished surface is observed using a scanning electron microscope (SEM, device: Carl Zeiss Gemini450 (trademark)) equipped with an electron beam backscatter diffraction device (EBSD device: Oxford Symmetry (trademark)), and EBSD analysis is performed on the obtained observed image.
• SEM scanning electron microscope
• EBSD electron beam backscatter diffraction device
• the observation area is set at the central portion of the treated surface of the cemented carbide, that is, at a position that does not include a portion that is clearly different from the bulk portion such as the vicinity of the surface of the cemented carbide (the observation area is the bulk portion of the cemented carbide).
• the measurement area is a rectangular area of 85 ⁇ m ⁇ 115 ⁇ m on the mirror-finished surface.
• the measurement conditions are acceleration voltage of 15 kV, current value of 20 nA, 40 nm/step, exposure time of 0.1 to 1 ms, and measurement time of 1 to 2 hours.
• the orientation difference between adjacent pairs is measured for all WC grains in the above measurement area. If a part of the WC grain is out of the measurement area, the WC grain is taken as the target of the misorientation measurement.
• two WC particles adjacent to each other means that at least part of one WC particle and at least part of another WC particle are in contact with each other. If two measurement points in the vicinity of EBSD are both identified as WC, and the difference in crystal orientation is 10° or more at the boundary between the two measurement points (corresponding to the interface of WC grains), the two measurement points are determined to be different WC grains.
• the above orientation difference measurement is performed in three different measurement areas. Based on the sum of the measurements of the three measurement areas, the software is used to generate a histogram showing the distribution of misorientation between adjacent pairs of two adjacent tungsten carbide grains in the three measurement areas. This histogram corresponds to the histogram of the cemented carbide of the first embodiment.
• the cemented carbide of Embodiment 1 can be produced, for example, by the following method.
• Tungsten carbide (WC) powder is prepared as a raw material for tungsten carbide particles.
• Raw materials for the binder phase include cobalt (Co) powder, iron (Fe) powder, and nickel (Ni) powder.
• Raw materials for the hard phase particles include TiC powder, TiN powder, TiCN powder, NbC powder, TaC powder, ZrC powder, Mo2C powder, TiO2 powder, Nb2O5 powder, and solid solutions and composites thereof.
• Chromium carbide (Cr 3 C 2 ) powder and vanadium carbide (VC) powder can be used as grain growth inhibitors.
• the average particle size of the tungsten carbide (WC) powder can be 0.1 ⁇ m or more and 3.5 ⁇ m or less.
• the cobalt (Co) powder may have an average particle size of 0.5 ⁇ m or more and 3.5 ⁇ m or less.
• the iron (Fe) powder can have an average particle size of 0.5 ⁇ m or more and 3.5 ⁇ m or less.
• the average particle size of the nickel (Ni) powder can be 0.5 ⁇ m or more and 3.5 ⁇ m or less.
• Chromium carbide (Cr 3 C 2 ) powder can have an average particle size of 0.5 ⁇ m or more and 3.5 ⁇ m or less.
• the vanadium carbide (VC) powder can have an average particle size of 0.5 ⁇ m or more and 3.5 ⁇ m or less.
• the average particle size of the raw material powder means the number-based median diameter d50 of the equivalent sphere diameters of the raw material powder.
• the average particle size of the raw material powder is measured using a particle size distribution analyzer (trade name: MT3300EX) manufactured by Microtrack.
• the raw material powders are mixed to obtain a mixed powder.
• An attritor or ball mill can be used for mixing.
• the mixing time in the attritor can be from 4 hours to 18 hours.
• the mixing time in the ball mill can be 4 hours or more and 72 hours or less.
• the compact is degreased by heating to 800° C. in vacuum.
• CIP Cold Isostatic Pressing
• the sintering conditions are an argon atmosphere, 7 MPa, heating to 1380° C. at a heating rate of 10° C./min, and a holding time at 1380° C. of 2 hours.
• a nitrogen atmosphere may be used instead of the argon atmosphere.
• the sintered body is rapidly cooled in an argon atmosphere. Subsequently, the sintered body after cooling is subjected to HIP (HIP: Hot Isostatic Pressing) to obtain a cemented carbide.
• HIP Hot Isostatic Pressing
• the HIP conditions can be 1330° C. and 200 MPa with a holding time of 2 hours.
• the tool of this embodiment comprises the cemented carbide of embodiment 1.
• examples of such tools include cutting tools, drills, end mills, indexable cutting inserts for milling, indexable cutting inserts for turning, metal saws, gear cutting tools, reamers and taps.
• the cemented carbide of this embodiment may constitute the whole of these tools, or may constitute a part of them.
• the term "constituting a part” indicates a mode of forming a cutting edge portion by brazing the cemented carbide of the present embodiment at a predetermined position of an arbitrary base material.
• the cutting tool according to the present embodiment may further include a hard film that covers at least part of the surface of the substrate made of cemented carbide.
• a hard film that covers at least part of the surface of the substrate made of cemented carbide.
• diamond-like carbon or diamond can be used as the hard film.
• the raw material powders were mixed at the ratio described in the "raw material powder" column of Table 1 to obtain a mixed powder.
• sample 1 contains 99.9% by volume of WC powder and 0.1% by volume of Co powder in 100% by volume of mixed powder.
• these powders were used in an amount obtained by equally dividing the whole hard phase raw material powder (% by volume).
• the total hard phase raw material powder is 20% by volume, and its breakdown is 10% by volume of TiCN powder and 10% by volume of NbC powder.
• An attritor was used for mixing. Mixing time in the attritor is 8 hours.
• the obtained mixed powder was press-molded into a tool shape (model SEET13T3AGSN-G (Sumitomo Electric Hardmetal Co., Ltd.)), and then subjected to high-pressure pressing to obtain a compact.
• the pressure of the high pressure press was 100 MPa.
• the compact was degreased by heating to 800° C. in vacuum.
• CIP is performed on the compact after degreasing.
• the CIP pressure was 392 MPa, and the treatment time was 60 minutes.
• the sintering conditions were an argon atmosphere, 7 MPa, heating to 1380° C. at a heating rate of 10° C./min, and holding time at 1380° C. for 2 hours.
• the sintered body was quenched in an argon atmosphere. Subsequently, the sintered body after cooling was subjected to HIP to obtain a cemented carbide.
• the HIP conditions were 1330° C. and 200 MPa for a holding time of 2 hours.
• Example a to sample c Raw material powders were mixed at the ratios shown in the "raw material powders" column of Table 1 to obtain mixed powders. An attritor was used for mixing. Mixing time in the attritor is 8 hours.
• the obtained mixed powder was press-molded into a tool shape (model number SEET13T3AGSN-G (Sumitomo Electric Hardmetal Co., Ltd.)). No high pressure pressing was performed. Next, the compact was degreased by heating to 800° C. in vacuum. CIP after degreasing was not performed.
• the sintering conditions were an argon atmosphere, 7 MPa, heating to 1380° C. at a heating rate of 10° C./min, and holding time at 1380° C. for 2 hours.
• the sintered body was quenched in an argon atmosphere. Subsequently, the sintered body after cooling was subjected to HIP to obtain a cemented carbide.
• the HIP conditions were 1330° C. and 200 MPa for a holding time of 2 hours.
• the distribution of misorientation between adjacent pairs was measured and a histogram was created.
• a specific measuring method is as described in the first embodiment. Based on the histogram, the peak frequency A in the class of misorientation of 29.5 ° or more and less than 30.5 °, the range of misorientation of 24.5 ° or more and less than 29.5 °, and the maximum frequency a1 of 10 classes of misorientation of 30.5 ° or more and less than 35.5 °, the peak frequency B of the class of misorientation of 89.5 ° or more and less than 90.5 °, the range of misorientation of 85.5 ° or more and less than 89.5 °, and The maximum value b1 of the frequency of eight classes in the range of 90.5° or more and less than 94.5° in the misorientation was obtained.
• ⁇ Tool> A tool for each sample was attached to a cutter (model number WGC4100R (Sumitomo Electric Hardmetal Co., Ltd.)), and milling was performed on an S45C block material (with a hole of ⁇ 6 mm).
• the machining conditions were: cutting speed Vc 250 m/min, table feed F 0.45 mm/min, depth of cut (axial direction) ap 2.0 mm, depth of cut (radial direction) ae 50 mm, and dry machining.
• the working length was measured until a chip was generated in the tool starting from a crack.
• the maximum processing length was 900 mm. The longer the working length, the better the chipping resistance and the longer the tool life.
• the results are shown in the "Life” column of "Tool” in Table 2. "No chipping" in the "Lifetime” column indicates that no chipping occurred at the processing length of 900 mm.

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• 2022
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