WO2022230364A1 - 超硬合金及びそれを用いた超高圧発生装置用金型 - Google Patents
超硬合金及びそれを用いた超高圧発生装置用金型 Download PDFInfo
- Publication number
- WO2022230364A1 WO2022230364A1 PCT/JP2022/009484 JP2022009484W WO2022230364A1 WO 2022230364 A1 WO2022230364 A1 WO 2022230364A1 JP 2022009484 W JP2022009484 W JP 2022009484W WO 2022230364 A1 WO2022230364 A1 WO 2022230364A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- cemented carbide
- phase
- less
- area
- mass
- Prior art date
Links
- 239000011651 chromium Substances 0.000 claims abstract description 59
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 59
- 239000010941 cobalt Substances 0.000 claims abstract description 57
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 57
- 239000002245 particle Substances 0.000 claims abstract description 50
- 238000005259 measurement Methods 0.000 claims abstract description 43
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 39
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 37
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 31
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims abstract description 29
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims abstract description 28
- 238000012545 processing Methods 0.000 claims abstract description 10
- 238000001000 micrograph Methods 0.000 claims description 14
- 239000000956 alloy Substances 0.000 claims description 9
- 229910045601 alloy Inorganic materials 0.000 claims description 9
- 230000000007 visual effect Effects 0.000 abstract description 10
- 239000012071 phase Substances 0.000 description 176
- 239000000843 powder Substances 0.000 description 35
- 238000000034 method Methods 0.000 description 32
- 238000005452 bending Methods 0.000 description 28
- 238000009616 inductively coupled plasma Methods 0.000 description 13
- 239000011812 mixed powder Substances 0.000 description 13
- INZDTEICWPZYJM-UHFFFAOYSA-N 1-(chloromethyl)-4-[4-(chloromethyl)phenyl]benzene Chemical compound C1=CC(CCl)=CC=C1C1=CC=C(CCl)C=C1 INZDTEICWPZYJM-UHFFFAOYSA-N 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 239000012535 impurity Substances 0.000 description 10
- 238000005245 sintering Methods 0.000 description 10
- 238000002156 mixing Methods 0.000 description 9
- 238000000465 moulding Methods 0.000 description 9
- 239000002994 raw material Substances 0.000 description 9
- 238000001816 cooling Methods 0.000 description 6
- 229910003460 diamond Inorganic materials 0.000 description 6
- 239000010432 diamond Substances 0.000 description 6
- 238000004993 emission spectroscopy Methods 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 5
- 238000003763 carbonization Methods 0.000 description 5
- UFGZSIPAQKLCGR-UHFFFAOYSA-N chromium carbide Chemical compound [Cr]#C[Cr]C#[Cr] UFGZSIPAQKLCGR-UHFFFAOYSA-N 0.000 description 5
- 229910003470 tongbaite Inorganic materials 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 238000003384 imaging method Methods 0.000 description 4
- 238000000691 measurement method Methods 0.000 description 4
- 150000001247 metal acetylides Chemical class 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 239000003966 growth inhibitor Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000000445 field-emission scanning electron microscopy Methods 0.000 description 2
- 238000005469 granulation Methods 0.000 description 2
- 230000003179 granulation Effects 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 238000010884 ion-beam technique Methods 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000007545 Vickers hardness test Methods 0.000 description 1
- 229910009043 WC-Co Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- -1 cobalt tungsten carbides Chemical class 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000009036 growth inhibition Effects 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- ZLANVVMKMCTKMT-UHFFFAOYSA-N methanidylidynevanadium(1+) Chemical class [V+]#[C-] ZLANVVMKMCTKMT-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000003918 potentiometric titration Methods 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000001226 reprecipitation Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000005491 wire drawing Methods 0.000 description 1
Images
Classifications
-
- 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
Definitions
- the present disclosure relates to a cemented carbide and a mold for an ultrahigh pressure generator using the same.
- This application claims priority from International Patent Application PCT/JP2021/016989 filed on April 28, 2021. The entire contents of that international patent application are incorporated herein by reference.
- Tungsten carbide-cobalt (WC-Co) cemented carbide which has excellent mechanical properties, is used for molds for ultra-high pressure generators (for example, Patent Documents 1 to 7).
- the cemented carbide of the present disclosure comprises a first phase composed of a plurality of tungsten carbide grains and a second phase comprising cobalt,
- the cemented carbide contains chromium and vanadium,
- the mass-based percentage of the chromium with respect to the cobalt is 5% or more and 9% or less,
- the mass-based percentage of the vanadium with respect to the cobalt is 2% or more and 5% or less
- the area ratio of the second phase is 7.5 area% or more and 13.5 area% or less
- the number of the second phases is 1000 or more,
- the area ratio of the second phase and the number of the second phases are measured in a measurement field of 101 ⁇ m 2 by performing image processing on a scanning electron microscope image of a cross section of the cemented carbide. alloy.
- the mold for an ultra-high pressure generator of the present disclosure is a mold for an ultra-high pressure generator made of the cemented carbide described above.
- FIG. 1 is an example of a scanning electron microscope image of a cemented carbide according to Embodiment 1.
- FIG. FIG. 2 is an image obtained by binarizing the image in FIG.
- a very high pressure of up to about 20 GPa is applied to the mold for the ultra-high pressure generator when the ultra-high pressure generator is used. Under such ultra-high pressure, breakage tends to occur and tool life tends to be shortened. Therefore, there is a demand for a mold for an ultrahigh pressure generator that has a long tool life even when used under ultrahigh pressure.
- the cemented carbide of the present disclosure is a cemented carbide comprising a first phase composed of a plurality of tungsten carbide grains and a second phase containing cobalt,
- the cemented carbide contains chromium and vanadium,
- the mass-based percentage of the chromium with respect to the cobalt is 5% or more and 9% or less,
- the mass-based percentage of the vanadium with respect to the cobalt is 2% or more and 5% or less
- the area ratio of the second phase is 7.5 area% or more and 13.5 area% or less
- the number of the second phases is 1000 or more,
- the area ratio of the second phase and the number of the second phases are measured in a measurement field of 101 ⁇ m 2 by performing image processing on a scanning electron microscope image of a cross section of the cemented carbide. alloy.
- cemented carbide of the present disclosure it is possible to obtain a mold for an ultra-high pressure generator having a long tool life even under ultra-high pressure.
- the area ratio of the second phase is preferably 7.5 area % or more and 11.5 area % or less. According to this, it is possible to obtain an optimum balance between hardness and bending strength in the use of molds for ultra-high pressure generators.
- the content of cobalt in the cemented carbide is preferably 4% by mass or more and 8% by mass or less. According to this, it is possible to obtain an optimum balance between hardness and bending strength in the use of molds for ultra-high pressure generators.
- the mass-based percentage of chromium relative to cobalt is preferably 7% or more and 8% or less. According to this, the cemented carbide can obtain stable bending strength and maintain a fine structure regardless of the carbon content.
- the mass-based percentage of vanadium relative to cobalt is preferably 2% or more and 4% or less. According to this, the cemented carbide can obtain stable bending strength and maintain a fine structure regardless of the carbon content.
- the number of second phases is preferably 1000 or more and 1100 or less. According to this, the cemented carbide can obtain a fine structure and a high Vickers hardness.
- the average particle size of the tungsten carbide particles is preferably 0.05 ⁇ m or more and 0.3 ⁇ m or less. According to this, the hardness of the cemented carbide is improved.
- the area ratio of the first phase is preferably 86.5 area % or more and 92.5 area % or less. According to this, the hardness and wear resistance of the cemented carbide are improved.
- the cemented carbide preferably consists of the first phase and the second phase. According to this, the bending strength of the cemented carbide is improved.
- a mold for an ultrahigh pressure generator of the present disclosure is a mold for an ultrahigh pressure generator made of the cemented carbide described above.
- the ultra-high pressure generator mold of the present disclosure can have a long tool life even under ultra-high pressure.
- a to B means the upper and lower limits of a range (that is, A to B inclusive), and if no unit is stated in A and only a unit is stated in B, then the The unit and the unit of B are the same.
- the atomic ratio when a compound or the like is represented by a chemical formula, when the atomic ratio is not particularly limited, it includes all conventionally known atomic ratios, and is not necessarily limited only to those within the stoichiometric range.
- any one numerical value described in the lower limit and any one numerical value described in the upper limit shall also be disclosed.
- a1 or more, b1 or more, c1 or more is described as the lower limit, and a2 or less, b2 or less, or c2 or less is described as the upper limit, a1 or more and a2 or less, a1 or more and b2 or less, a1 or more and c2 or less, b1 to a2, b1 to b2, b1 to c2, c1 to a2, c1 to b2, and c1 to c2.
- a cemented carbide according to one embodiment of the present disclosure (hereinafter also referred to as "this embodiment") is a cemented carbide comprising a first phase composed of a plurality of tungsten carbide particles and a second phase containing cobalt.
- the cemented carbide comprises chromium and vanadium;
- the mass-based percentage of the chromium with respect to the cobalt is 5% or more and 9% or less,
- the mass-based percentage of the vanadium with respect to the cobalt is 2% or more and 5% or less,
- the area ratio of the second phase is 7.5 area% or more and 13.5 area% or less,
- the number of the second phase is 1000 or more,
- the area ratio of the second phase and the number of the second phase are measured in a measurement field of 101 ⁇ m 2 by performing image processing on a scanning electron microscope image of a cross section of the cemented carbide. alloy.
- the cemented carbide of this embodiment comprises a first phase consisting of a plurality of tungsten carbide grains and a second phase comprising cobalt, and further comprising chromium and vanadium.
- the first phase consists of a plurality of tungsten carbide grains (hereinafter also referred to as "WC grains").
- the first phase is a hard phase.
- the first phase can contain unavoidable impurity elements and the like in addition to WC particles. From the viewpoint of achieving the effects of the present disclosure, the content of WC particles in the first phase is preferably 99% by mass or more, more preferably 99.9% by mass or more, and more preferably substantially 100% by mass.
- the first phase can contain unavoidable impurity elements, trace impurity elements, etc. mixed in the manufacturing process of the WC particles, as long as the effects of the present disclosure are exhibited.
- impurity elements include, for example, molybdenum (Mo) and chromium (Cr).
- the content of impurity elements in the first phase is preferably 1% by mass or less, 0.1% by mass or less, and less than 0.1% by mass. .
- the content of impurity elements in the first phase is measured by ICP (Inductively Coupled Plasma) emission spectrometry (measuring device: "ICPS-8100" (trademark) manufactured by Shimadzu Corporation).
- the area ratio of the first phase is preferably 86.5 area % or more and 92.5 area % or less.
- the area ratio of the first phase is measured in a measurement field of 101 ⁇ m 2 by performing image processing on a scanning electron microscope image of a cross section of the cemented carbide. According to this, cemented carbide can have high hardness and excellent wear resistance.
- the lower limit of the area ratio of the first phase is preferably 86.5 area % or more, 87.0 area % or more, and 88.5 area % or more from the viewpoint of improving the hardness and wear resistance of the cemented carbide.
- the upper limit of the area ratio of the first phase is preferably 92.5 area % or less.
- the area ratio of the first phase is preferably 86.5 area % or more and 92.5 area % or less, 87.0 area % or more and 92.5 area % or less, and 88.5 area % or more and 92.5 area % or less. The details of the method for measuring the area ratio of the first phase will be described later.
- the area ratio of the second phase is 7.5 area % or more and 13.5 area % or less, and the number of the second phases is 1000 or more.
- a plurality of WC particles constituting the second phase are fine, and the plurality of WC particles are dispersed in the second phase.
- the average particle size of the plurality of WC particles can be, for example, 0.05 ⁇ m or more and 0.3 ⁇ m or less.
- the cemented carbide of the present embodiment contains a small amount of coarse (for example, grain size of 2 ⁇ m or more and 5 ⁇ m or less) WC particles (for example, 20 or less per 1 mm 2 cross section of the cemented carbide) ).
- the lower limit of the average particle size of WC particles is preferably 0.05 ⁇ m or more, 0.06 ⁇ m or more, or 0.08 ⁇ m or more.
- the upper limit of the average particle diameter of WC particles is preferably 0.3 ⁇ m or less, 0.27 ⁇ m or less, or 0.23 ⁇ m or less.
- the average particle size of the WC particles is preferably 0.05 ⁇ m to 0.3 ⁇ m, 0.06 ⁇ m to 0.27 ⁇ m, and 0.08 ⁇ m to 0.23 ⁇ m.
- the average particle size of the above WC particles is measured by the following procedure.
- a sample having a smooth cross section is obtained by subjecting the cemented carbide to CP (Cross Section Polisher) processing using an argon ion beam or the like.
- CP Cross Section Polisher
- SEM-BSE image scanning electron microscope image of the cross section of the sample.
- the imaging conditions are an imaging magnification of 5000 times, an acceleration voltage of 5 kV, and a work distance of 10.0 mm.
- a measurement field of 1 mm 2 (1 mm ⁇ 1 mm rectangle) is set in the scanning electron microscope image.
- image analysis software ImageJ ver.1.51j8 (https://imagej.nih.gov/ij/)
- the outer edge of each WC particle in the measurement field was identified, and the equivalent circle diameter of each WC particle was determined.
- Calculate A number-based arithmetic mean diameter of equivalent circle diameters of all WC particles in the measurement field is calculated.
- the arithmetic mean diameter is measured at five different measurement fields without overlapping.
- the average value of the arithmetic mean diameters of the WC particles in the five measurement fields is calculated. This average value corresponds to the average particle size of the WC particles in this embodiment.
- the second phase contains cobalt (Co).
- the second phase is the binder phase.
- the second phase may contain chromium (Cr), vanadium (V), unavoidable impurity elements, and the like.
- inevitable impurity elements include iron (Fe), nickel (Ni), manganese (Mn), magnesium (Mg), calcium (Ca), molybdenum (Mo), sulfur (S), titanium (Ti), aluminum ( Al) and the like.
- the cobalt content of the second phase is preferably 85% by mass or more and 100% by mass or less.
- the content of elements other than cobalt in the second phase (the total content when two or more of these elements are present) is preferably 0% by mass or more and less than 1% by mass.
- the content of elements other than cobalt in the second phase is measured by ICP (Inductively Coupled Plasma) emission spectrometry (measuring device: "ICPS-8100" (trademark) manufactured by Shimadzu Corporation).
- the area ratio of the second phase is 7.5 area % or more and 13.5 area % or less, and the number of the second phases is 1000 or more.
- the area ratio of the second phase and the number of second phases are measured in a measurement field of 101 ⁇ m 2 by performing image processing on a scanning electron microscope image of a cross section of the cemented carbide.
- the cemented carbide can have excellent toughness.
- the lower limit of the area ratio of the second phase is preferably 7.5 area % or more.
- the upper limit of the area ratio of the second phase is 13.5 area% or less, 13.0 area% or less, 11.5 area% or less, 11.5 area% or less, from the viewpoint of improving the hardness and wear resistance of the cemented carbide. % or less is preferable.
- the area ratio of the second phase is preferably 7.5 area % or more and 13.5 area % or less, 7.5 area % or more and 13.0 area % or less, or 7.5 area % or more and 11.5 area % or less.
- the cemented carbide will break even under ultrahigh pressure. hard. Although the reason for this is not clear, in the cemented carbide, since fine WC particles (first phase) are dispersed in the second phase, the strength of the second phase is improved, and the cemented carbide This is probably because the hardness, bending strength and high-temperature strength of the steel were improved.
- the area ratio of the second phase is 7.5 area % or more and 13.5 area % or less, and the number of second phases is 1000 or more.
- the lower limit of the number of second phases is preferably 1,000 or more, 1,010 or more, 1,020 or more, 1,030 or more, or 1,040 or more from the viewpoint of the crystal grain content and the fineness of the structure.
- the upper limit of the number of second phases is preferably 1,200 or less, 1,150 or less, or 1,100 or less from the viewpoint of improving bending strength and fracture toughness.
- the number of second phases is 1000 or more and 1200 or less, 1010 or more and 1200 or less, 1020 or more and 1150 or less, 1030 or more and 1150 or less, 1040 1100 or less is preferable.
- the number of the second phase is from the viewpoint of improving the strength and fracture toughness, the number is preferably 1,000 to 1,200, 1,010 to 1,200, 1,020 to 1,150, 1,030 to 1,150, and 1,040 to 1,100.
- a sample with a smooth cross section is obtained by CP (Cross Section Polisher) processing of the cemented carbide using an argon ion beam or the like.
- CP Cross Section Polisher
- SEM-BSE image scanning electron microscope image of the cross section of the sample.
- the photographing conditions are a photographing magnification of 10,000 times, an acceleration voltage of 5 kV, and a work distance of 10.0 mm, and photographing is performed as a backscattered electron image.
- FIG. 1 An example of a scanning electron microscope image of the cemented carbide according to this embodiment is shown in FIG.
- the gray area corresponds to the first phase
- the black area corresponds to the second phase.
- a measurement field of 101 ⁇ m 2 (11.88 ⁇ m ⁇ 8.5 ⁇ m rectangle) is set in the scanning electron microscope image.
- FIG. 2 shows an image obtained by binarizing the scanning electron microscope image of FIG. In FIG. 2, the white area corresponds to the first phase, and the black area corresponds to the second phase.
- the sum (total area) of the areas of all the first phases in the above measurement field is calculated.
- the percentage of the total area of the first phase with respect to the entire measurement visual field is calculated, taking the entire measurement visual field as 100 area %. This percentage corresponds to the area ratio of the first phase in the measurement field.
- the sum (total area) of all the areas of the second phase in the above measurement field is calculated.
- the percentage of the total area of the second phase with respect to the entire measurement visual field is calculated, taking the entire measurement visual field as 100 area %. This percentage corresponds to the area ratio of the second phase in the measurement field.
- the number of second phases in the measurement visual field is measured based on the binarization process. From the shape of the second phase, when it is considered that the second phase is formed by bonding or contacting two or more second phases, the number of second phases in the shape is judged to be one.
- 5 measurement fields are set so that there are no overlapping parts, and in each of the 5 fields, the area ratio of the first phase and the second phase in the measurement field, and the measurement field Obtain the number of second phases in the
- the average value of the area ratio of the first phase in the five measurement visual fields corresponds to the "area ratio of the first phase in the measurement visual field" in this specification.
- the average value of the area ratio of the second phase in the five measurement fields corresponds to the "area ratio of the second phase in the measurement field” in this specification.
- the average value of the number of second phases in the five measurement visual fields corresponds to "the number of second phases in the measurement visual field" in this specification.
- the cobalt content of the cemented carbide of the present embodiment is preferably 4% by mass or more and 8% by mass or less. According to this, cemented carbide can have excellent toughness. From the viewpoint of improving toughness, the lower limit of the cobalt content of the cemented carbide is preferably 4% by mass or more, 4.5% by mass or more, and 5% by mass or more. From the viewpoint of improving wear resistance, the upper limit of the cobalt content of the cemented carbide is preferably 8% by mass or less, 7.5% by mass or less, or 7% by mass or less.
- the cobalt content of the cemented carbide is 4% by mass or more and 8% by mass or less, 4.5% by mass or more and 7.5% by mass or less, 5% by mass or more and 7% by mass or less. is preferred.
- Cobalt content in the cemented carbide is obtained by analysis by TAS0054:2017 cobalt potentiometric titration method for cemented carbide.
- the mass-based percentage of chromium with respect to cobalt is 5% or more and 9% or less.
- Chromium has an effect of suppressing grain growth of tungsten carbide grains.
- Chromium is usually added as carbides of chromium such as Cr 3 C 2 in the cemented carbide manufacturing process.
- the lower limit of the mass-based percentage of chromium with respect to cobalt is preferably 5% or more, 5.5% or more, 6% or more, 6.6% or more, and 7% or more from the viewpoint of improving grain growth suppressing action.
- the upper limit of the mass-based percentage of chromium with respect to cobalt is preferably 9% or less, 8.5% or less, or 8% or less from the viewpoint of improving bending strength and fracture toughness.
- the mass-based percentage of chromium with respect to cobalt is 5% or more and 9% or less, 5.5% or more and 8.5% or less, 6% or more and 8% or less, 6 .6% or more and 8% or less, preferably 7% or more and 8% or less.
- the mass-based percentage of chromium with respect to cobalt in the cemented carbide of the present embodiment is determined by analyzing the cobalt content and chromium content of the cemented carbide by ICP (inductively coupled plasma emission spectroscopy).
- the lower limit of the mass-based percentage of chromium is preferably 0.20% or more, 0.25% or more, and 0.30% or more.
- the mass-based content of chromium is preferably 0.72% or less, 0.65% or less, or 0.60% or less.
- the mass-based percentage of chromium is preferably 0.20% or more and 0.72% or less, 0.25% or more and 0.65% or less, and 0.30% or more and 0.60% or less.
- the mass-based percentage of chromium in the cemented carbide of this embodiment is measured by ICP (Inductively Coupled Plasma Emission Spectroscopy).
- the mass-based percentage of vanadium with respect to cobalt is 2% or more and 5% or less. Vanadium has an effect of suppressing grain growth of tungsten carbide grains. Vanadium is usually added as vanadium carbides such as VC in the manufacturing process of cemented carbide.
- the lower limit of the mass-based percentage of vanadium relative to cobalt can be 2% or more, 2.1% or more, 2.2% or more, or 3% or more from the viewpoint of improving grain growth suppressing action.
- the upper limit of the mass-based percentage of vanadium relative to cobalt is preferably 5% or less, 4.5% or less, or 4% or less from the viewpoint of improving bending strength and fracture toughness.
- the mass-based percentage of vanadium with respect to cobalt is 2% or more and 5% or less, 2.1% or more and 5% or less, and 2.1% or more and 4.5% or less, from the viewpoint of improving grain growth suppressing action and improving hardness.
- the mass-based percentage of vanadium with respect to cobalt is obtained by analyzing the cobalt content and vanadium content of the cemented carbide by ICP (inductively coupled plasma emission spectroscopy).
- the lower limit of the mass-based percentage of vanadium is preferably 0.08% or more, 0.10% or more, and 0.12% or more.
- the mass-based content of vanadium is preferably 0.30% or less, 0.35% or less, or 0.40% or less.
- the mass-based percentage of vanadium is preferably 0.08% or more and 0.40% or less, 0.10% or more and 0.35% or less, and 0.12% or more and 0.30% or less.
- the mass-based percentage of vanadium in the cemented carbide of this embodiment is measured by ICP (inductively coupled plasma emission spectroscopy).
- the cemented carbide of the present embodiment consists of a first phase and a second phase, and substantially includes phases other than the first phase and the second phase (also referred to as "third phase" in this specification). preferably not.
- the cemented carbide of this embodiment preferably consists of a first phase and a second phase.
- the cemented carbide of the present embodiment can contain unavoidable impurities in addition to the first phase and the second phase as long as the effect of the present disclosure is exhibited.
- An example of the third phase is one in which Cr or V contained in Cr 3 C 2 or VC added as a grain growth inhibitor forms a different phase from the first and second phases.
- Cr 3 C 2 and VC added as grain growth inhibitors form a third phase separate from the first and second phases.
- the third phase acts as a starting point for fracture, lowering the bending strength, and also serves as a starting point for fracture of the mold for an ultra-high pressure generator, shortening the life of the cemented carbide.
- the third phase does not exist in the cemented carbide, it does not act as a starting point for fracture, so the transverse rupture strength is improved and the life of the mold for the ultra-high pressure generator is improved.
- the present inventors have found that the presence of Cr or V on the boundary between the first phase and the second phase or in the second phase improves the grain growth inhibition effect rather than the presence of Cr or V in the third phase. Assuming that, as a result of intensive studies, a method for producing a cemented carbide substantially free of the third phase was established, and the cemented carbide of the present embodiment was obtained.
- substantially free of the third phase does not exclude the presence of a trace amount of the third phase as long as the effects of the present disclosure are not achieved.
- Whether or not the above-described third phase exists in the cemented carbide is determined by analyzing the cemented carbide structure by wavelength dispersive X-ray analysis (WDX) using the field emission scanning electron microscope described above. can be confirmed. Details of the WDX are described in Reference 1 (Hisashi Suzuki, Kei Tokumoto (1984). Structure and mechanical properties of WC-Cr 3 C 2 -15% Co cemented carbide, Powder and Powder Metallurgy, Vol. 31). 2, 56-59.). If the third phase is present in the cemented carbide, the WDX analysis confirms Cr, V and C enriched phases.
- WDX wavelength dispersive X-ray analysis
- the above-mentioned third phase is substantially absent, no Cr, V, and C-enriched phases are confirmed in the above WDX analysis.
- the above-mentioned third phase does not substantially exist, it does not become the starting point of fracture, so the bending strength is improved, and the life is extended when used for a mold for an ultra-high pressure generator. improves.
- tertiary phases are carbon - poor cobalt tungsten carbides, known as eta phases, e.g., Co3W3C , Co6W6C , Co2W4C , Co3W9C4 . mentioned.
- the ⁇ phase tends to be the starting point of fracture. Since the cemented carbide according to the present embodiment does not contain an ⁇ phase, the bending strength is improved, and the life of the cemented carbide is improved when used for a mold for an ultra-high pressure generator.
- the following procedure confirms whether or not the ⁇ phase exists in the cemented carbide. After grinding the surface of the cemented carbide with a diamond wheel using diamond particles with an average particle size of 150 ⁇ m, it is polished by a predetermined thickness with diamond paste with an average particle size of 1 ⁇ m. The polished surface is etched to observe the structure. When the ⁇ phase exists in the superconcave alloy, a structure in which the ⁇ phase is preferentially etched is confirmed.
- the Vickers hardness Hv30 of the cemented carbide of this embodiment is preferably 1950 or more. According to this, the wear resistance of the cemented carbide is improved.
- the lower limit of the Vickers hardness is preferably 1950 or more, 2000 or more, or 2030 or more from the viewpoint of improving wear resistance.
- the upper limit of the Vickers hardness is preferably 2500 or less, 2300 or less, or 2200 or less from the viewpoint of improving wear resistance.
- the Vickers hardness is preferably 1950 or more and 2500 or less, 2000 or more and 2300 or less, or 2030 or more and 2200 or less.
- the Vickers hardness is measured according to JISZ2244:2009 Vickers hardness test.
- the measurement conditions are room temperature (23° C. ⁇ 5° C.), a test load of 294.2 N (30 kgf, Hv30), and a holding time of 20 seconds.
- the bending strength of the cemented carbide of this embodiment is preferably 2.8 GPa or more. According to this, the life of the mold for the ultra-high pressure generator is improved.
- the lower limit of the bending strength is preferably 2.8 GPa or more, 3.0 GPa or more, or 3.2 GPa or more from the viewpoint of improving the life of the mold for the ultra-high pressure generator.
- the upper limit of the bending strength is not particularly limited, it can be 6.0 GPa or less from the viewpoint of manufacturing.
- the bending strength of the cemented carbide is 2.8 GPa or more and 6.0 GPa or less, 3.0 GPa or more and 6.0 GPa or less, or 3.2 GPa or more and 6.0 GPa or less from the viewpoint of improving the life of the mold for the ultra-high pressure generator. preferable.
- the above bending strength is measured according to CIS026B-2007 Cemented Carbide Alloy Bending Strength (Bending Strength) Test Method.
- the test piece size is 4 mm ⁇ 8 mm ⁇ 25 mm
- the load point/fulcrum size is R2.0 mm
- the fulcrum span is 20 mm.
- the measurement temperature is room temperature (23° C. ⁇ 5° C.).
- the cemented carbide of this embodiment can be suitably used for tools used under ultrahigh pressure.
- tools used under ultrahigh pressure include dies for ultra-high pressure generators, wire drawing dies, extrusion dies, rolling rolls, can manufacturing tools, forging dies, powder molding dies, and the like.
- the cemented carbide of this embodiment can be manufactured, for example, by the following method.
- the cemented carbide of this embodiment may be manufactured by methods other than the following.
- the cemented carbide of the present embodiment can typically be produced by performing the raw material powder preparation process, mixing process, molding process, sintering process, and cooling process in the above order. Each step will be described below.
- the preparation step is a step of preparing all the raw material powders of the materials that constitute the cemented carbide.
- raw material powders tungsten carbide powder as the raw material of the first phase, cobalt (Co) powder as the raw material of the second phase, and chromium carbide (Cr 3 C 2 ) powder and vanadium carbide (VC) as grain growth inhibitors.
- tungsten carbide powder, cobalt powder, chromium carbide powder, and vanadium carbide powder can be used.
- the tungsten carbide powder it is preferable to use tungsten carbide powder carbonized at a temperature of 1400° C. or higher and 1600° C. or lower.
- the particle size of the tungsten carbide powder is preferably about 0.1 to 0.3 ⁇ m. According to this, the stability of WC grains is enhanced at the stage of appearance of the liquid phase during sintering, dissolution and reprecipitation are suppressed, a fine cemented carbide structure is obtained, and coarse WC grains are less likely to occur. As an effect of this, the amount of Cr 3 C 2 and VC added for the purpose of suppressing grain growth can be kept low, and the precipitation of the third phase in the cemented carbide structure, which causes a decrease in strength, can be suppressed.
- the average particle size of the raw material powder is the average particle size measured by the FSSS (Fisher Sub-Sieve Sizer) method (measuring device: "Fisher Sub-Sieve Sizer Model 95" (trademark) manufactured by Fisher Scientific). means diameter.
- tungsten carbide powder that has been carbonized at a temperature of 1100° C. or higher and 1350° C. or lower has been pulverized to a particle size of 0.1 to 0.3 ⁇ m.
- the tungsten carbide powder is fine, the tungsten carbide is dissolved and reprecipitated in cobalt during sintering, resulting in an increase in the grain size of the WC grains and a tendency to lower the hardness of the cemented carbide.
- the average particle size of the cobalt powder can be 0.4 ⁇ m or more and 1.0 ⁇ m or less (FSSS method).
- the average particle size of the chromium carbide powder can be 0.5 ⁇ m or more and 3 ⁇ m or less (FSSS method).
- the average particle size of the vanadium carbide powder can be 0.5 ⁇ m or more and 3 ⁇ m or less (FSSS method).
- the mixing step is a step of mixing each raw material powder prepared in the preparation step.
- a mixed powder in which each raw material powder is mixed is obtained by the mixing step.
- the content of the tungsten carbide powder in the mixed powder can be, for example, 90.88% by mass or more and 95.72% by mass or less.
- the content of cobalt powder in the mixed powder can be, for example, 4% by mass or more and 8% by mass or less.
- the content of the chromium carbide powder in the mixed powder can be, for example, 0.2% by mass or more and 0.72% by mass or less.
- the content of the vanadium carbide powder in the mixed powder can be, for example, 0.08% by mass or more and 0.4% by mass or less.
- the mixed powder is mixed using a ball mill.
- the media diameter can be 1 mm to 10 mm.
- the rotation speed can be 10-120 rpm.
- Mixing time can be from 20 hours to 48 hours.
- the mixed powder may be granulated as needed.
- it is easy to fill the mixed powder into a die or mold during the molding process described below.
- a known granulation method can be applied for granulation, and for example, a commercially available granulator such as a spray dryer can be used.
- the molding step is a step of molding the mixed powder obtained in the mixing step into a predetermined shape to obtain a compact.
- General methods and conditions may be adopted for the molding method and molding conditions in the molding step, and are not particularly limited.
- the predetermined shape may be, for example, the shape of a mold for an ultrahigh pressure generator (for example, the shape of an anvil).
- the sintering step is a step of sintering the compact obtained in the forming step to obtain a cemented carbide.
- the sintering temperature can be 1340 to 1450° C.
- the sintering time can be 30 to 180 minutes. According to this, generation of coarse tungsten carbide particles is suppressed.
- HIP treatment may be performed under conditions of 1340 to 1450° C., 10 MPa to 200 MPa, and 0.5 to 2 hours.
- a cooling process is a process of cooling the cemented carbide after completion of sintering.
- the cooling rate is preferably 2°C/min to 10°C/min. According to this, abnormal grain growth is suppressed.
- the cemented carbide of the present embodiment can be obtained through the above steps. This was newly discovered by the present inventors as a result of extensive studies.
- the mold for an ultrahigh pressure generator of this embodiment is made of the cemented carbide of the first embodiment.
- Examples of molds for ultrahigh pressure generators include anvils and pistons.
- the mold for an ultrahigh pressure generator of this embodiment can have a long tool life even under ultrahigh pressure.
- the area ratio of the first phase is 86.5 area% or more and 92.5 area% or less
- the area ratio of the second phase is preferably 7.5 area % or more and 13.5 area % or less.
- the area ratio of the first phase is 88.5 area% or more and 92.5 area% or less
- the area ratio of the second phase is preferably 7.5 area % or more and 11.5 area % or less.
- the Vickers hardness Hv30 of the cemented carbide of the present disclosure is preferably 1950 or more and 2500 or less.
- the bending strength of the cemented carbide of the present disclosure is preferably 2.8 GPa or more and 5.0 GPa or less.
- cemented carbides of the present disclosure are preferably free of ⁇ -phase.
- the cobalt content of the second phase is preferably 85% by mass or more and 100% by mass or less.
- Tungsten carbide powder (average particle size 0.1-0.2 ⁇ m, carbonization temperature 1400° C.) or tungsten carbide powder (average particle size 0.1-0.2 ⁇ m, carbonization temperature less than 1400° C.), and cobalt (Co) powder (average particle size 0.8 ⁇ m), chromium carbide (Cr 3 C 2 ) powder (average particle size 1.0 ⁇ m) and vanadium carbide (VC) powder (average particle size 0.9 ⁇ m) were prepared. Samples 1-1 to 1-5 used the tungsten carbide powder having a carbonization temperature of less than 1400°C. For other samples, the tungsten carbide powder with a carbonization temperature of 1400° C. is used.
- the above mixed powder was press molded at a pressure of 1000 kg/cm 2 , heated to 1350° C. in vacuum, and sintered at 1350° C. for 1 hour. After that, HIP treatment was performed under the conditions of 1350 ° C., 100 MPa, 1 hour, and then cooled to 20 ° C. at a cooling rate of 10 ° C./min. 10 mm) was obtained.
- the “remainder” in the “WC (mass%)” column means that the content of WC is the value obtained by subtracting the sum of the Co content, Cr content and V content from 100 mass% of the entire cemented carbide. indicates For example, sample 1 has a WC content of 95.00% by mass.
- Samples 1 to 23 correspond to Examples.
- Samples 1-1 to 1-8 and samples 2-1 to 2-13 correspond to comparative examples. It was confirmed that Samples 1 to 23 (Examples) had longer lives than Samples 1-1 to 1-8 and Samples 2-1 to 2-13 (Comparative Examples). This is because, in Samples 1 to 23 (Example), the contents of Cr and V, which suppress the grain growth of WC grains, are moderate, so that the structure is refined and the third phase that can be the starting point of fracture is not generated, and it is presumed that destruction is unlikely to occur.
- Samples 1 to 16 have 1000 or more second phases
- Samples 1-1 to 1-5 which correspond to conventional alloys, have the number of second phases. (702 to 801), it can be seen that the number is large and a very fine structure is obtained.
- the carbonization temperature of the raw material WC particles used is less than 1400° C., a fine structure cannot be obtained, and the number of second phases in the structure is small.
- Samples 1-6 had a small Cr/Co ratio, could not obtain a fine structure, and had an insufficient tool life.
- Samples 1-7 had a small V/Co, could not obtain a fine structure, and had an insufficient tool life.
- Sample 1-8 had a large V/Co ratio and insufficient bending strength, so the tool life was insufficient.
- Samples 2-1 to 2-6 which correspond to conventional alloys, had excessive Cr/Co and/or V/Co, so a fine structure was obtained, but Cr/Co and/or V/Co was excessive. Therefore, it has been confirmed that the bending strength or hardness tends to be low, and the life is shortened when used in an ultrahigh pressure mold.
- Sample 2-7 had an insufficient tool life because the area ratio of the second phase was small and the bending strength was low.
- Sample 2-8 had a large area ratio of the second phase and lacked hardness, so the tool life was insufficient.
- Sample 2-9 had a small Cr/Co ratio, could not obtain a fine structure, and lacked hardness, so the tool life was insufficient.
- Sample 2-10 had insufficient tool life due to lack of hardness due to lack of microstructure.
- Sample 2-11 had insufficient tool life due to lack of hardness due to lack of microstructure.
- Sample 2-12 had a large Cr/Co ratio and lacked hardness, so the tool life was insufficient.
- Sample 2-13 had a large V/Co and insufficient hardness, so the tool life was insufficient.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Powder Metallurgy (AREA)
Abstract
Description
前記超硬合金は、クロム及びバナジウムを含み、
前記コバルトに対する前記クロムの質量基準の百分率は、5%以上9%以下であり、
前記コバルトに対する前記バナジウムの質量基準の百分率は、2%以上5%以下であり、
前記第2相の面積比率は、7.5面積%以上13.5面積%以下であり、
前記第2相の個数は1000個以上であり、
前記第2相の面積比率及び前記第2相の個数は、前記超硬合金の断面の走査型電子顕微鏡像に対して画像処理を行うことにより、101μm2の測定視野において測定される、超硬合金である。
超高圧発生装置用金型には、超高圧発生装置の使用時に最大約20GPaの非常に高い圧力が加わる。このような超高圧下では、破損が生じやすく、工具寿命が低下する傾向がある。よって、超高圧下での使用においても、長い工具寿命を有する超高圧発生装置用金型が求められている。
本開示の超硬合金によれば、超高圧下においても、長い工具寿命を有する超高圧発生装置用金型を得ることができる。
最初に本開示の実施態様を列記して説明する。
(1)本開示の超硬合金は、複数の炭化タングステン粒子からなる第1相と、コバルトを含む第2相と、を備える超硬合金であって、
前記超硬合金は、クロム及びバナジウムを含み、
前記コバルトに対する前記クロムの質量基準の百分率は、5%以上9%以下であり、
前記コバルトに対する前記バナジウムの質量基準の百分率は、2%以上5%以下であり、
前記第2相の面積比率は、7.5面積%以上13.5面積%以下であり、
前記第2相の個数は1000個以上であり、
前記第2相の面積比率及び前記第2相の個数は、前記超硬合金の断面の走査型電子顕微鏡像に対して画像処理を行うことにより、101μm2の測定視野において測定される、超硬合金である。
本開示の超硬合金及びそれを用いた超高圧発生装置用金型の具体例を、以下に図面を参照しつつ説明する。本開示の図面において、同一の参照符号は、同一部分または相当部分を表すものである。また、長さ、幅、厚さ、深さなどの寸法関係は図面の明瞭化と簡略化のために適宜変更されており、必ずしも実際の寸法関係を表すものではない。
本開示の一実施形態(以下「本実施形態」とも記す。)の超硬合金は、複数の炭化タングステン粒子からなる第1相と、コバルトを含む第2相と、を備える超硬合金であって、
該超硬合金は、クロム及びバナジウムを含み、
該コバルトに対する該クロムの質量基準の百分率は、5%以上9%以下であり、
該コバルトに対する該バナジウムの質量基準の百分率は、2%以上5%以下であり、
該第2相の面積比率は、7.5面積%以上13.5面積%以下であり、
該第2相の個数は1000個以上であり、
該第2相の面積比率及び該第2相の個数は、該超硬合金の断面の走査型電子顕微鏡像に対して画像処理を行うことにより、101μm2の測定視野において測定される、超硬合金である。
本実施形態の超硬合金は、複数の炭化タングステン粒子からなる第1相と、コバルトを含む第2相と、を備え、更に、クロム及びバナジウムを含む。
本実施形態の超硬合金において、第1相は、複数の炭化タングステン粒子(以下、「WC粒子」とも記す。)からなる。本実施形態の超硬合金において、第1相は硬質相である。第1相は、WC粒子の他、不可避不純物元素などを含むことができる。第1相におけるWC粒子の含有率は、本開示の効果を奏する観点から、99質量%以上が好ましく、99.9質量%以上がより好ましく、実質的に100質量%であることがより好ましい。
本実施形態の超硬合金において、第1相の面積比率は、86.5面積%以上92.5面積%以下であることが好ましい。第1相の面積比率は、超硬合金の断面の走査型電子顕微鏡像に対して画像処理を行うことにより、101μm2の測定視野において測定される。これによると、超硬合金は高い硬度及び優れた耐摩耗性を有することができる。第1相の面積比率の下限は、超硬合金の硬度向上及び耐摩耗性向上の観点から、86.5面積%以上、87.0面積%以上、88.5面積%以上が好ましい。第1相の面積比率の上限は、超硬合金の靱性向上の観点から、92.5面積%以下が好ましい。第1相の面積比率は、86.5面積%以上92.5面積%以下、87.0面積%以上92.5面積%以下、88.5面積%以上92.5面積%以下が好ましい。第1相の面積比率の測定方法の詳細は後述する。
本実施形態の超硬合金は、第2相の面積比率が7.5面積%以上13.5面積%以下であり、かつ、第2相の個数が1000個以上であるため、第1相を構成する複数のWC粒子が微細であり、かつ、第2相中に複数のWC粒子が分散して存在している。該複数のWC粒子の平均粒径は、例えば0.05μm以上0.3μm以下とすることができる。ただし、本実施形態の超硬合金は、本開示の効果を奏する限り、粗大(例えば、粒径2μm以上5μm以下)なWC粒子を微量(例えば、超硬合金の断面1mm2当たり、20個以下)含むことができる。
本実施形態の超硬合金において、第2相はコバルト(Co)を含む。本実施形態の超硬合金において、第2相は結合相である。第2相はコバルトの他、クロム(Cr)、バナジウム(V)、不可避不純物元素などを含むことができる。不可避不純物元素としては、たとえば、鉄(Fe)、ニッケル(Ni)、マンガン(Mn)、マグネシウム(Mg)、カルシウム(Ca)、モリブデン(Mo)、硫黄(S)、チタン(Ti)、アルミニウム(Al)などが挙げられる。第2相のコバルト含有率は、85質量%以上100質量%以下が好ましい。第2相中のコバルト以外の元素の含有率(該元素が2種類以上の場合は、合計含有率)は、0質量%以上1質量%未満であることが好ましい。第2相中のコバルト以外の元素の含有率は、ICP(Inductively Coupled Plasma)発光分析(測定装置:島津製作所製「ICPS-8100」(商標))により測定される。
本実施形態の超硬合金において、第2相の面積比率は、7.5面積%以上13.5面積%以下であり、第2相の個数は1000個以上である。第2相の面積比率及び第2相の個数は、超硬合金の断面の走査型電子顕微鏡像に対して画像処理を行うことにより、101μm2の測定視野において測定される。
本明細書において、第1相及び第2相の面積比率、及び、第2相の個数の測定方法は以下の通りである。
(a)Edit→Invert
(b)上記(a)の後に、Process→Binary→MakeBinary
(c)上記(b)の後に、Process→Noise→Despeckle。前記(c)の操作を3回繰り返す。(c)におけるNoise除去回数は、第2相の個数に影響を及ぼすため、本実施形態では、(c)の操作の回数は3回と固定する。
(d)上記(c)の後に、Process→Binary→Watershed
図1の走査型電子顕微鏡像に対して2値化処理を行った画像を図2に示す。図2において、白色で示される領域が第1相に該当し、黒色で示される部分が第2相に該当する。
本実施形態の超硬合金のコバルト含有率は、4質量%以上8質量%以下が好ましい。これによると、超硬合金は優れた靱性を有することができる。超硬合金のコバルト含有率の下限は、靱性向上の観点から、4質量%以上、4.5質量%以上、5質量%以上が好ましい。超硬合金のコバルト含有率の上限は、耐摩耗性向上の観点から、8質量%以下、7.5質量%以下、7質量%以下が好ましい。超硬合金のコバルト含有率は、靱性向上及び耐摩耗性向上の観点から、4質量%以上8質量%以下、4.5質量%以上7.5質量%以下、5質量%以上7質量%以下が好ましい。超硬合金中のコバルト含有率はTAS0054:2017超硬質合金のコバルト電位差滴定定量法にて分析することで求められる。
本実施形態の超硬合金において、コバルトに対するクロムの質量基準の百分率は、5%以上9%以下である。クロムは炭化タングステン粒子の粒成長抑制作用を有する。通常、クロムは、超硬合金の製造工程において、Cr3C2等のクロムの炭化物として添加される。
本実施形態の超硬合金において、コバルトに対するバナジウムの質量基準の百分率は、2%以上5%以下である。バナジウムは炭化タングステン粒子の粒成長抑制作用を有する。通常、バナジウムは、超硬合金の製造工程において、VC等のバナジウムの炭化物として添加される。
本実施形態の超硬合金は、第1相及び第2相からなり、実質的に第1相及び第2相以外のその他の相(本明細書において「第3相」とも記す。)を含まないことが好ましい。本実施形態の超硬合金は、第1相と、第2相とからなることが好ましい。本実施形態の超硬合金は、本開示の効果を奏する限り、第1相及び第2相に加えて、不可避不純物を含むことができる。
本実施形態の超硬合金のビッカース硬度Hv30は、1950以上が好ましい。これによると、超硬合金の耐摩耗性が向上する。該ビッカース硬度の下限は、耐摩耗性向上の観点から、1950以上、2000以上、2030以上が好ましい。該ビッカース硬度の上限は、耐摩耗性向上の観点から、2500以下、2300以下、2200以下が好ましい。該ビッカース硬度は、1950以上2500以下、2000以上2300以下、2030以上2200以下が好ましい。
本実施形態の超硬合金の抗折強度は、2.8GPa以上が好ましい。これによると、超高圧発生装置用金型の寿命が向上する。抗折強度の下限は、超高圧発生装置用金型の寿命向上の観点から、2.8GPa以上、3.0GPa以上、3.2GPa以上が好ましい。該抗折強度の上限は、特に限定されないが、製造上の観点から、6.0GPa以下とすることができる。超硬合金の抗折強度は、超高圧発生装置用金型の寿命向上の観点から、2.8GPa以上6.0GPa以下、3.0GPa以上6.0GPa以下、3.2GPa以上6.0GPa以下が好ましい。
本実施形態の超硬合金は、超高圧下で使用される工具に好適に用いることができる。このような工具としては、超高圧発生装置用金型、線引きダイス、押出ダイス、圧延ロール、製缶工具、鍛造用金型、粉末成型金型などが挙げられる。
本実施形態の超硬合金は、例えば、下記の方法で製造することができる。なお、本実施形態の超硬合金は、下記以外の方法で製造されてもよい。
準備工程は、超硬合金を構成する材料の全ての原料粉末を準備する工程である。原料粉末としては、第1相の原料である炭化タングステン粉末、第2相の原料であるコバルト(Co)粉末、粒成長抑制剤として、炭化クロム(Cr3C2)粉末及び炭化バナジウム(VC)粉末を準備する。炭化タングステン粉末、コバルト粉末、炭化クロム粉末、炭化バナジウム粉末は、市販のものを用いることができる。
混合工程は、準備工程で準備した各原料粉末を混合する工程である。混合工程により、各原料粉末が混合された混合粉末が得られる。
成形工程は、混合工程で得られた混合粉末を所定の形状に成形して、成形体を得る工程である。成形工程における成形方法及び成形条件は、一般的な方法及び条件を採用すればよく、特に問わない。所定の形状としては、例えば、超高圧発生装置用金型形状(例えば、アンビルの形状)とすることが挙げられる。
焼結工程は、成形工程で得られた成形体を焼結して、超硬合金を得る工程である。本実施形態の超硬合金の製造方法においては、焼結温度は1340~1450℃、焼結時間は30~180分とすることができる。これによると、粗大炭化タングステン粒子の発生が抑制される。その後、1340~1450℃、10MPa~200MPa、0.5~2時間の条件でHIP処理を行っても良い。
冷却工程は、焼結完了後の超硬合金を冷却する工程である。冷却速度は2℃/分~10℃/分とすることが好ましい。これによると、異常粒成長が抑制される。
本実施形態の超高圧発生装置用金型は、実施形態1の超硬合金からなる。超高圧発生装置用金型としては、例えば、アンビル、ピストンが挙げられる。本実施形態の超高圧発生装置用金型は、超高圧下においても、長い工具寿命を有することができる。
本開示の超硬合金において、
前記第1相の面積比率は、86.5面積%以上92.5面積%以下であり、
前記第2相の面積比率は、7.5面積%以上13.5面積%以下であることが好ましい。
本開示の超硬合金において、
前記第1相の面積比率は、88.5面積%以上92.5面積%以下であり、
前記第2相の面積比率は、7.5面積%以上11.5面積%以下であることが好ましい。
本開示の超硬合金のビッカース硬度Hv30は、1950以上2500以下が好ましい。
本開示の超硬合金の抗折強度は、2.8GPa以上5.0GPa以下が好ましい。
本開示の超硬合金は、η相を含まないことが好ましい。
本開示の超硬合金において、第2相のコバルト含有率は、85質量%以上100質量%以下が好ましい。
第1相及び第2相の面積比率、第2相の個数、炭化タングステン粒子の平均粒径、Co含有率、Cr含有率及びV含有率が異なる種々の超硬合金を作製し、合金特性を測定した。試験に用いた超硬合金は、以下のように作製した。
≪Co、Cr、Vの含有率≫
各試料において、Co、Cr、Vの含有率を測定した。測定方法は実施形態1に記載されているため、その説明は繰り返さない。結果を表1及び表2の「Co(質量%)」、「Cr(質量%)」、「V(質量%)欄に示す。これらの値に基づき、「コバルトに対するクロムの質量基準の百分率(Cr/Co)」及び「コバルトに対するバナジウムの質量基準の百分率(V/Co)」を算出した。結果を表1及び表2の「Cr/Co(%)」及び「V/Co(%)」欄に示す。「WC(質量%)」欄における「残」とは、超硬合金全体100質量%から、Co含有率、Cr含有率及びV含有率の合計を減じた値が、WCの含有率であることを示す。例えば、試料1では、WC含有率は95.00質量%である。
各試料において、第1相及び第2相の面積比率、第2相の個数を測定した。測定方法は実施形態1に記載されているため、その説明は繰り返さない。結果を表1及び表2の「第1相面積比率(面積%)」、「第2相面積比率(面積%)」、「第2相個数」欄に示す。
各試料において、第2相のコバルト以外の元素の含有率をICPで測定し、その値を第2相全体(100質量%)から減じることにより、第2相のコバルト含有率を測定した。全ての試料において、第2相のコバルト含有率は、85質量%以上であることが確認された。
各試料において、ビッカース硬度(Hv30)を測定した。測定方法は実施形態1に記載されているため、その説明は繰り返さない。結果を表1及び表2の「硬度 Hv30」欄に示す。
得られた超硬合金において、抗折強度を測定した。測定方法は実施形態1に記載されているため、その説明は繰り返さない。結果を表1及び表2の「抗折強度(GPa)」欄に示す。
各試料の超硬合金を用いて、8個の立方体で構成されるマルチアンビルを作製し、該マルチアンビルを用いてグラファイト粉末に対して16GPa及び2200℃の条件下で高温高圧処理を行い、ダイヤモンドを作製した。各試料において、同一のマルチアンビルを用いて上記のダイヤモンドの作製を複数回行い、1個以上のマルチアンビルに破損が生じた場合の作製回数を工具寿命とした。例えば、5回目のダイヤモンドの作製時に1個以上のマルチアンビルに破損が生じた場合は、工具寿命は5回となる。試料1-1の工具寿命を1.0とした場合の、各試料の工具寿命の割合を表1及び表2の「寿命」欄に示す。例えば、試料1は寿命が「11.0」である。これは、試料1の工具寿命が、試料1-1の工具寿命の11倍であることを意味する。
試料1~試料23は実施例に該当する。試料1-1~試料1-8及び試料2-1~試料2-13は比較例に該当する。試料1~試料23(実施例)は、試料1-1~試料1-8及び試料2-1~試料2-13(比較例)に比べて、寿命が長いことが確認された。これは、試料1~試料23(実施例)では、WC粒子の粒成長を抑制するCr及びVの含有量が適度であるため、組織が微細化しているとともに、破壊の起点となり得る第3相が生成されておらず、破壊が生じ難いためと推察される。
今回開示された実施の形態および実施例はすべての点で例示であって、制限的なものではないと考えられるべきである。本発明の範囲は上記した実施の形態および実施例ではなく請求の範囲によって示され、請求の範囲と均等の意味、および範囲内でのすべての変更が含まれることが意図される。
Claims (10)
- 複数の炭化タングステン粒子からなる第1相と、コバルトを含む第2相と、を備える超硬合金であって、
前記超硬合金は、クロム及びバナジウムを含み、
前記コバルトに対する前記クロムの質量基準の百分率は、5%以上9%以下であり、
前記コバルトに対する前記バナジウムの質量基準の百分率は、2%以上5%以下であり、
前記第2相の面積比率は、7.5面積%以上13.5面積%以下であり、
前記第2相の個数は1000個以上であり、
前記第2相の面積比率及び前記第2相の個数は、前記超硬合金の断面の走査型電子顕微鏡像に対して画像処理を行うことにより、101μm2の測定視野において測定される、超硬合金。 - 前記第2相の面積比率は、7.5面積%以上11.5面積%以下である、請求項1に記載の超硬合金。
- 前記超硬合金のコバルト含有率は、4質量%以上8質量%以下である、請求項1又は請求項2に記載の超硬合金。
- 前記コバルトに対する前記クロムの質量基準の百分率は、7%以上8%以下である、請求項1から請求項3のいずれか1項に記載の超硬合金。
- 前記コバルトに対する前記バナジウムの質量基準の百分率は、2%以上4%以下である、請求項1から請求項4のいずれか1項に記載の超硬合金。
- 前記第2相の個数は1000個以上1100個以下である、請求項1から請求項5のいずれか1項に記載の超硬合金。
- 前記炭化タングステン粒子の平均粒径は、0.05μm以上0.3μm以下である、請求項1から請求項6のいずれか1項に記載の超硬合金。
- 前記第1相の面積比率は、86.5面積%以上92.5面積%以下である、請求項1から請求項7のいずれか1項に記載の超硬合金。
- 前記超硬合金は、前記第1相と、前記第2相とからなる、請求項1から請求項8のいずれか1項に記載の超硬合金。
- 請求項1から請求項9のいずれか1項に記載の超硬合金からなる超高圧発生装置用金型。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202280004581.9A CN115768913A (zh) | 2021-04-28 | 2022-03-04 | 硬质合金及使用了该硬质合金的超高压发生装置用模具 |
EP22795287.6A EP4249618A1 (en) | 2021-04-28 | 2022-03-04 | Cemented carbide, and mold which is for ultrahigh-pressure generating device and uses same |
JP2022540599A JP7131738B1 (ja) | 2021-04-28 | 2022-03-04 | 超硬合金及びそれを用いた超高圧発生装置用金型 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JPPCT/JP2021/016989 | 2021-04-28 | ||
PCT/JP2021/016989 WO2022230110A1 (ja) | 2021-04-28 | 2021-04-28 | 超硬合金及びそれを用いた超高圧発生装置用金型 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2022230364A1 true WO2022230364A1 (ja) | 2022-11-03 |
Family
ID=83848107
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2021/016989 WO2022230110A1 (ja) | 2021-04-28 | 2021-04-28 | 超硬合金及びそれを用いた超高圧発生装置用金型 |
PCT/JP2022/009484 WO2022230364A1 (ja) | 2021-04-28 | 2022-03-04 | 超硬合金及びそれを用いた超高圧発生装置用金型 |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2021/016989 WO2022230110A1 (ja) | 2021-04-28 | 2021-04-28 | 超硬合金及びそれを用いた超高圧発生装置用金型 |
Country Status (1)
Country | Link |
---|---|
WO (2) | WO2022230110A1 (ja) |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001181777A (ja) | 1999-12-24 | 2001-07-03 | Fuji Dies Kk | 超高圧発生装置用シリンダーコアおよびアンビルコア |
JP2008038242A (ja) | 2006-08-08 | 2008-02-21 | Fuji Dies Kk | 超微粒超硬合金 |
WO2009001929A1 (ja) * | 2007-06-27 | 2008-12-31 | Kyocera Corporation | 超硬合金、切削工具ならびに切削加工装置 |
JP2015081382A (ja) | 2013-10-24 | 2015-04-27 | 住友電工ハードメタル株式会社 | 超硬合金、マイクロドリル、及び超硬合金の製造方法 |
JP2015108162A (ja) | 2013-10-22 | 2015-06-11 | 冨士ダイス株式会社 | Ni少量添加WC−Co基超硬合金またはそれを用いた工具 |
JP2016098421A (ja) | 2014-11-25 | 2016-05-30 | 冨士ダイス株式会社 | 遅れ破壊しない超硬合金を用いた超高圧発生用容器 |
CN111378886A (zh) | 2018-12-28 | 2020-07-07 | 自贡硬质合金有限责任公司 | 一种超细晶硬质合金及其制备方法 |
-
2021
- 2021-04-28 WO PCT/JP2021/016989 patent/WO2022230110A1/ja active Application Filing
-
2022
- 2022-03-04 WO PCT/JP2022/009484 patent/WO2022230364A1/ja active Application Filing
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001181777A (ja) | 1999-12-24 | 2001-07-03 | Fuji Dies Kk | 超高圧発生装置用シリンダーコアおよびアンビルコア |
JP2008038242A (ja) | 2006-08-08 | 2008-02-21 | Fuji Dies Kk | 超微粒超硬合金 |
WO2009001929A1 (ja) * | 2007-06-27 | 2008-12-31 | Kyocera Corporation | 超硬合金、切削工具ならびに切削加工装置 |
JP2015108162A (ja) | 2013-10-22 | 2015-06-11 | 冨士ダイス株式会社 | Ni少量添加WC−Co基超硬合金またはそれを用いた工具 |
JP2015081382A (ja) | 2013-10-24 | 2015-04-27 | 住友電工ハードメタル株式会社 | 超硬合金、マイクロドリル、及び超硬合金の製造方法 |
JP2016098421A (ja) | 2014-11-25 | 2016-05-30 | 冨士ダイス株式会社 | 遅れ破壊しない超硬合金を用いた超高圧発生用容器 |
CN111378886A (zh) | 2018-12-28 | 2020-07-07 | 自贡硬质合金有限责任公司 | 一种超细晶硬质合金及其制备方法 |
Non-Patent Citations (1)
Title |
---|
HISASHI SUZUKIKEI TOKUMOTO, MICROSTRUCTURES AND MECHANICAL PROPERTIES OF WC-CR C -15%CO CEMENTED CARBIDE, POWDER AND POWDER METALLURGY, vol. 31, no. 2, 1984, pages 56 - 59 |
Also Published As
Publication number | Publication date |
---|---|
WO2022230110A1 (ja) | 2022-11-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6796266B2 (ja) | 超硬合金、及び切削工具 | |
JP4773416B2 (ja) | 焼結体の製造方法、該方法に用いる粉末混合物、該方法により製造された焼結体 | |
JP5309394B2 (ja) | 超硬合金 | |
JP2010514933A (ja) | 冷間成形用の耐食性工具 | |
JP2005239472A (ja) | 高強度・高耐摩耗性ダイヤモンド焼結体およびその製造方法 | |
JP2005068547A (ja) | 均一な固溶体粒子構造を有する超微細結晶粒のサーメット製造方法 | |
CN109070216A (zh) | 具有韧性增强结构的碳化物 | |
KR20100014777A (ko) | 다이아몬드 소결체 및 그 제조 방법 | |
CN114786843A (zh) | 超细硬质合金和使用该超细硬质合金的切割用或切削用工具或耐磨用工具 | |
WO2015166730A1 (ja) | 複合焼結体 | |
KR102552550B1 (ko) | 서멧, 그것을 포함하는 절삭 공구 및 서멧의 제조 방법 | |
JP7103565B1 (ja) | 超硬合金およびそれを基材として含む切削工具 | |
JP2010208942A (ja) | 高強度・高耐摩耗性ダイヤモンド焼結体およびその製造方法 | |
WO2022230364A1 (ja) | 超硬合金及びそれを用いた超高圧発生装置用金型 | |
JP7131738B1 (ja) | 超硬合金及びそれを用いた超高圧発生装置用金型 | |
TWI748676B (zh) | 超硬合金及具備其之切削工具 | |
JP5085799B1 (ja) | 結合相をNiとした超微粒超硬合金およびそれを用いた工具 | |
JP5740763B2 (ja) | 超硬合金 | |
WO2023135807A1 (ja) | 超高圧発生装置用金型 | |
Deng et al. | Physical properties and microstructure of Ti (CN)-based cermets with different WC particle size | |
EP4296390A1 (en) | Cemented carbide | |
JP7215806B1 (ja) | 超硬合金及びそれを用いた切削工具 | |
WO2023175721A1 (ja) | 超硬合金 | |
JP7251691B1 (ja) | 超硬合金およびそれを含む工具 | |
EP4372115A1 (en) | Cemented carbide and cutting tool using same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ENP | Entry into the national phase |
Ref document number: 2022540599 Country of ref document: JP Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 17922004 Country of ref document: US |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 22795287 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2022795287 Country of ref document: EP Effective date: 20230620 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |