JPH11124650A - Wc-containing cemented carbide subjected to transgranular dispersion strengthening by oxide, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve, to a greater extent, the characteristics, as unsatisfactory as ever, of a plate-crystal-WC-containing cemented carbide improved in toughness as well as in hardness, among conventional cemented carbides. SOLUTION: In this cemented carbide consisting of 5-35 vol.% of binding phase composed essentially of iron group metal and the balance hard phase composed of tungsten carbide, the hard phase contains a transgranular dispersion strengthened tungsten carbide where an oxide-containing transgranular dispersoid is dispersed in the grain of tungsten carbide. Further, the proportion of the total content of the transgranular dispersoid is regulated to >=0.01 vol.%, based on the whole tungsten carbide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cemented carbide containing tungsten carbide with intragranular dispersion strengthened by dispersing oxide fine particles in crystal grains of tungsten carbide, and a method for producing the same. By uniformly dispersing an oxide that is finer than tungsten carbide in the crystal grains and is stable at the sintering temperature during the manufacturing process, residual stress is added in the tungsten carbide crystal grains to obtain a cemented carbide. The hardness, toughness, abrasion resistance, fracture resistance, plastic deformation resistance, heat crack resistance, etc., of cutting tools, dies and punches for milling and turning inserts, drills, end mills, etc. Mold tools, cutting tools such as slitters, cutting tools, nozzles, wear-resistant tools and parts represented by mechanical seals, and various bits used for drilling, crushing, etc. The best oxide as civil engineering tool that relates WC-containing hard metal and its preparation reinforced intragranular distributed.

[0002]

2. Description of the Related Art Generally, material properties such as hardness and toughness of a cemented carbide tend to have a trade-off that when one is improved, the other is reduced. There have been proposed a large number of cemented carbides containing platelet WC and methods for producing the same in order to simultaneously improve both properties of hardness and toughness. As typical prior art relating to the cemented carbide containing the platelet crystal WC, Japanese Patent Application Laid-Open Nos. 7-258785, 7-292426, and 7-3 by the present inventors.
No. 16688. In addition, although it is different from liquid phase sintering cemented carbide, it is a nanocomposite material in which ultrafine particles of other components are dispersed in matrix particles as a material that improves performance by simultaneously improving material properties. Many sintered bodies have been proposed. As typical prior arts of nanocomposite materials related to this ceramic sintered body, Japanese Patent Application Laid-Open Nos. Hei 2-229756, Hei 2-229775, Hei 6-116
No. 038 and JP-A-6-116072.

[0003]

Among prior arts relating to a typical cemented carbide having both improved hardness and toughness at the same time, Japanese Patent Application Laid-Open No. Hei 7-258785 discloses a hexagonal carbide contained in a cemented carbide. When the ratio of the (001) crystal plane to the (101) crystal plane in the X-ray diffraction of tungsten is 0.
A WC-containing cemented carbide comprising at least 50 platelets is disclosed. Also, Japanese Patent Application Laid-Open No. 7-292426 discloses that, when heating and sintering a powder of Co and / or Ni, a carbon source, and W, or a mixed powder of W and WC,
A first process in which a WC-based, Ni-WC-based, or Co-Ni-WC-based composite carbide is produced, and a second process in which plate-like crystals WC are produced by a reaction between the composite carbide and residual carbon. And a process for producing a platelet-shaped WC-containing cemented carbide comprising the steps of: Further, Japanese Patent Application Laid-Open No. 7-316638 discloses that Co and / or Ni powder, a carbon source, WC, 4a, 5a,
When heating and sintering a mixed powder of a Group 6a metal and an oxygen-containing compound, Co-WC, Ni-WC, Co-Ni
A method for producing a plate-like WC-containing cemented carbide including a first process in which a WC-based composite carbide is generated, and a second process in which a plate-like crystal WC is generated by a reaction between the composite carbide and residual carbon. Are listed. The plate-shaped WC-containing cemented carbide disclosed in these three publications has improved hardness and toughness as compared with conventional cemented carbide. However, the present inventors were not satisfied with these platelet WC-containing cemented carbides,
The object was to further improve the properties of the cemented carbide.

Among the typical prior arts having improved material properties, Japanese Patent Application Laid-Open Nos. 2-229756 and 2-2
Japanese Patent No. 29575 discloses that the characteristics of an alumina-based ceramics sintered body are improved by dispersing nanoparticles of titanium nitride or titanium carbide in crystal grains of alumina. Japanese Patent Application Laid-Open Nos. 6-116038 and 6-116072 disclose that silicon carbide nanoparticles are dispersed in silicon nitride crystal grains to improve the characteristics of a silicon nitride-silicon carbide ceramic sintered body. Is disclosed. The ceramic sintered bodies disclosed in these publications improve the hardness by dispersing other particles in the grains of the matrix, suppress the development of fracture cracks by applying a stress field to the matrix grains, and improve the toughness. However, there is a problem that the toughness is inferior to that of a cemented carbide and cannot be practically used in a use region of a cemented carbide.

The present invention has solved the above-mentioned problems. More specifically, the present invention relates to a plate-like WC-containing cemented carbide described in detail as the prior art and a superalloy obtained by a method for producing the same. Hardness and toughness are improved by adding further improvements to hard alloys, mainly by selecting fine starting materials and dispersing fine oxides in tungsten carbide crystals during precipitation of tungsten carbide during heating in the sintering process. It is an object of the present invention to provide a WC-containing cemented carbide having an intragranular dispersion strengthened by an oxide having improved properties such as wear resistance, wear resistance, fracture resistance and impact resistance, and a method for producing the same.

[0006]

In a cemented carbide obtained by sintering a mixed powder of WC and Co, it is difficult to disperse fine particles of other components in the WC crystal. They have studied for many years how to simultaneously improve the hardness and toughness of cemented carbides, and from the results of many years study, adding fine Al ₂ O ₃ powder to a mixed powder of W, carbon and Co and sintering, Fine A in WC crystal generated and grown during sintering process
l ₂ O ₃ particles are taken up and dispersed, or
W and Al such as l-based alloy or W-Al-Co-based alloy
When Co and carbon powders are added to the starting raw material powder in which is uniformly dissolved as a solid and heated and sintered, fine Al ₂ O ₃ particles generated simultaneously are taken into the WC crystal generated and grown in the sintering process. And that the hardness and toughness of the WC crystal itself increase when this Al ₂ O _{3 3} is dispersed in the WC crystal. The cemented carbide containing WC intragranularly dispersed by Al ₂ O ₃ is: It has been found that the present invention is excellent in hardness, toughness, wear resistance, fracture resistance, impact resistance and the like, and has completed the present invention.

The cemented carbide according to the present invention is a cemented carbide containing 5-35% by volume of a binder phase mainly composed of an iron group metal and a hard phase composed of tungsten carbide. It contains intragranular dispersion-enhanced tungsten carbide in which an intragranular dispersion containing an oxide is dispersed in the grains of tungsten carbide, and the total content of the intragranular dispersion is 0.01% with respect to the entire tungsten carbide. % By volume or more.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The binder phase in the cemented carbide of the present invention is specifically Co, Ni, Co-Ni alloy, Fe-
Ni alloy and Co-W alloy, Ni-Cr alloy, Co-Cr-
V alloy, Co-Ni-Cr alloy, Co-Ni-W-Cr
Alloys or Fe-Ni-Co-W-Cr-Mo alloys. In some cases, Mg, A
When one or more of l and rare earth elements (including Sc and Y) are contained, they are alloyed with the binder phase and solid solution strengthened, or intermetallic compounds such as CoAl and Ni ₃ Al are precipitated to strengthen dispersion. Being high-temperature hardness, heat resistance, plastic deformation resistance,
It is preferable because the oxidation resistance and the like are further improved. If the content of the binder phase is less than 5% by volume with respect to the entire cemented carbide, burrows will remain in the alloy and strength, toughness and fracture resistance will be reduced. Conversely, if it exceeds 35% by volume, it will increase. , Hardness and abrasion resistance are reduced, so that the content is set to 5 to 35% by volume.

[0009] Tungsten carbide as a hard phase contained in addition to the binder phase is a hexagonal WC crystal,
Usually, it has a triangular prism-like appearance, but it is preferable to use a triangular or hexagonal plate-like crystal with a developed (001) plane, since the hardness and toughness are further improved at the same time. In addition, the tungsten carbide is contained as intragranular dispersion strengthened tungsten carbide in which an intragranular dispersion containing an oxide in the grains is dispersed.

When the cemented carbide of the present invention comprises the above-mentioned binder phase and a tungsten carbide hard phase in which intragranular dispersion strengthened tungsten carbide is mixed, in addition to these binder phase and the hard phase, the cemented carbide as a whole To 4a, 5a, 6 in the periodic table
When the cubic compound phase composed of at least one of carbides, carbonitrides, carbonates, carbonitrides and their mutual solid solutions of group a metal is contained at 55% by volume or less, the binder phase and the hard phase are hardened. In addition to the phase, an oxide dispersed phase composed of at least one of Mg, Al, and rare earth elements (including Sc, Y) is contained in an amount of 5% by volume or less with respect to the entire cemented carbide, or A typical example includes a binder phase, a hard phase, a cubic compound phase, and an oxide dispersed phase.

Of these, the cubic compound phase is specifically composed of Ti (CN), Zr (CN), HfN, (WT
i) C, (WTiTa) C, (WTiTa) (CN),
(WZr) (C0), (WHf) C and the like can be mentioned. When the amount of the cubic compound phase exceeds 55% by volume, the intragranular dispersion strengthened WC
Is relatively small and the effect of improving hardness and toughness is low.

When the oxide dispersed phase is uniformly dispersed as fine particles in the cubic compound phase and / or the binder phase, the hardness and toughness of the cemented carbide itself tend to be further improved. This is preferable because

[0013] The intragranular dispersion-strengthened tungsten carbide mixed in the hard phase tends to markedly increase hardness, strength and toughness when it is contained in an amount of 20% by volume or more based on the whole tungsten carbide. This is preferable. Further, a plate-like crystal represented by a triangular or hexagonal plate-like crystal in which the intragranular dispersion strengthened tungsten has a (001) plane developed,
Specifically, it is preferable that the tungsten carbide crystal in an arbitrary cross section is composed of plate-like tungsten carbide observed in a rod shape, a triangular shape, or a hexagonal shape, since the above-described characteristics tend to be further enhanced. That is.

The oxide which is uniformly dispersed in the grains of tungsten carbide and exists as an intragranular dispersion is not problematic as long as it is a stable oxide at the time of heating and sintering when producing a cemented carbide. Specifically, MgO, Al ₂ O ₃ , Y ₂ O ₃ , La
₂ O ₃ , CeO ₂ , Yb ₂ O ₃ , MgAl ₂ O ₄ , Y ₃ Al ₅ O
_An active metal oxide or a composite oxide composed of at least one of the above-mentioned compounds can be given as a typical example. In addition,
Basically, all of the stable oxides such as BeO, CaO, SrO, and ThO ₂ can be listed in the sintering process of cemented carbide, but from the viewpoints of dispersion effect, toxicity, radioactivity, reactivity with water, etc. At least one of Mg, Al, rare earth oxides and their mutual solid solution is preferred.

If the content of the oxide as an intragranular dispersion is less than 0.01% by volume based on the whole tungsten carbide, the proportion of the oxide particles taken into the WC crystal is reduced and the oxide dispersion is reduced. Since the effect of improving the hardness and toughness due to reinforcement tends to decrease, the content ratio of the oxide is set to 0.01%.
It was determined to be at least volume%. The content ratio of the oxide as an intragranular dispersion is preferably 0.01 to 1% by volume, because of difficulty in production, increase in pits generated in the obtained cemented carbide itself, and reduction in strength due to aggregation of the oxide. , Especially 0.02
It is preferable that the content is 0.5% by volume.

The intragranular dispersion may be composed of the above-mentioned oxide alone or composed of the oxide and another substance. Specific examples of other substances include carbides, nitrides, and the like.
It is composed of at least one of carbonitrides, carbonates, nitrides, carbonitrides, metals and alloys. Of these,
It is preferable that a metal and / or an alloy be contained as an oxide and another substance because the toughness of the intragranular dispersion strengthened tungsten carbide itself is enhanced. In particular, when the intragranular dispersion is composed of one or more oxides of Mg, Al and rare earth elements, and an alloy containing an iron group metal or an iron group element, it is more preferable to enhance toughness. It is.

The intragranular dispersion is preferably finely and uniformly dispersed, and specifically, has an average diameter of 0.5
μm or less, preferably 0.2 μm or less, more preferably 0.01 μm or less. The relationship between the size of the intragranular dispersion and the intragranular dispersion strengthened tungsten carbide is as follows:
Because of the simplicity in production and the tendency to significantly increase hardness, strength, and toughness, the average particle size of the intragranular dispersion strengthened tungsten carbide may be 3 to 300 times the average particle size of the intragranular dispersion. It is a good thing.

The cemented carbide according to the present invention is obtained by doping or ion-implanting an inorganic substance to be an intragranular dispersion into tungsten or tungsten carbide as a starting material, and using the doped or ion-implanted starting material. It is also conceivable to apply the method of manufacturing powder metallurgy described above. However, such a method is very difficult, the selection of the intragranular dispersion is limited, the process becomes complicated by the addition of the manufacturing process, and the manufacturing cost is increased. Is preferred.

In the method for producing a cemented carbide according to the present invention, a first step of mixing and pulverizing starting materials for producing a cemented carbide to form a mixed powder, and molding the mixed powder into a powder compact. A second step of heating and sintering the powder compact at 1200 to 1600 ° C. in a non-oxidizing atmosphere or in a vacuum to obtain a cemented carbide. A manufacturing method characterized by comprising a binder phase forming powder containing a metal as a main component, a W powder, a carbon source powder of carbon and / or graphite, and an oxide powder which is stable during the heat sintering. Is the way.

The binder phase forming powder contained as a starting material in this production method is a powder comprising the binder phase component mentioned in the above-mentioned cemented carbide, specifically, Co, Ni, F
e, Co-W alloy, Ni-Cr alloy, or Fe-Cr
A powder of a Ni alloy or the like can be given as a typical example.

The oxide powder contained as a starting material in this production method is a powder comprising the oxide dispersed phase component mentioned in the above-mentioned cemented carbide, specifically, Mg powder.
O, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Yb
One or more kinds of powders such as ₂ O ₃ , MgAl ₂ O ₄ , and Y ₃ Al ₅ O ₁₂ can be mentioned as typical examples. The average particle diameter of these oxide powders is preferably 0.5 μm or less, because the finer the particles, the more easily they are incorporated into the WC crystal. Also,
It is preferable to use a solution of a salt such as Mg (NO ₃ ) ₂ , AlCl ₃ , Y ₃ (NO ₃ ) _{2 because} oxides generated by thermal decomposition can be finely divided and uniformly dispersed.

As the cubic compound phase forming powder in the method for producing a cemented carbide according to the present invention, specifically, TiC, Zr
C, HfC, TiN, ZrN, HfN, VC, NbN,
TaC, TiO ₂ , ZrO ₂ , Hf (CN), Zr (C
O), (WTi) C, (WZr) (CO), (WTit
a) The case of one or more of C, (WTiTa) CN and the like can be mentioned.

As the alloy powder in the method for producing a cemented carbide according to the present invention, specifically, W-Al, WY, W-Ce, W
-Al-Co, W-Zr-Ni, W-Ta-Fe, and other alloys.

The manufacturing steps in the method of manufacturing a cemented carbide according to the present invention include: a step of mixing and pulverizing starting materials; a step of pressing and molding a mixed powder; And heat sintering. When the atmosphere in the sintering step is vacuum, the pressure is preferably in the range of 1 to 100 Pa. When the pressure is less than 1 Pa, the added oxide reacts with the carbide to easily decompose and disappear or generate gas.
This is because carbides such as iC are oxidized. In particular, when the starting material contains an alloy of W and an active metal, it reacts with the oxide in the mixed powder or oxygen in the atmosphere,
This is preferable because an oxide of the active metal is generated and sinterability is improved.

[0025]

According to the cemented carbide of the present invention, the intragranular dispersion containing the oxide is uniformly dispersed in the tungsten carbide grains, thereby imparting residual stress to the tungsten carbide grains and causing crack propagation in the grains. And has the effect of reducing defects in tungsten carbide that is recrystallized during sintering and the effect of strengthening the inside of the grains of tungsten carbide. The hardness, strength,
It acts to enhance toughness, thermal crack resistance and thermal shock resistance.

Further, the method of manufacturing a cemented carbide according to the present invention is characterized in that a WC crystal in which particles of an intragranular dispersion containing a fine oxide added to a mixed powder of W, carbon and Co are formed and grown in a sintering process. When WC crystals are generated and grown by the heating reaction between an alloy of W and the active metal and carbon, fine oxide particles of the active metal that are simultaneously oxidized and generated are taken in Rarely dispersed, the dispersed intragranular dispersion particles improve the hardness and toughness of the WC crystal at the same time. In particular, the WC crystal is uniformly dispersed in the cemented carbide, so that the strength, toughness, heat crack resistance and This has the effect of significantly increasing the thermal shock resistance.

[0027]

EXAMPLE 1 First, a commercially available average particle size of 1.5
μm W, about 3 μm Al, 1.2 μm Co, 1.7
Using each powder of Ni of μm, the mixture was weighed to the composition shown in Table 1, inserted into a stainless steel pot together with an acetone solvent and a cemented carbide ball, mixed and pulverized for 48 hours, and dried to obtain a mixed powder. Insert into a graphite crucible and pressurize at atmospheric pressure 0.1
Heat treatment was performed at 1400 ° C. × 1 hour in a vacuum of Pa to obtain alloy powders A1 to A3 for starting materials. These A
Table 1 also shows the composition results and particle sizes of the 1 to A3 powders by X-ray diffraction.

Next, the above-mentioned Co, Ni, Al, alloy powders A1 to A3 for starting materials and commercially available W having an average particle size of 2.0 μm, WC of 2.5 μm, and graphite of 4.5 μm (Table 1) In the description, “G” is used), and 1.0 μm (WTi) C
Composite carbide (WC / TiC = 70/30 by weight ratio),
1.0 μm TaC, 1.7 μm Cr ₃ C ₂ , 0.00
5 μm MgO, 0.01 μm Al ₂ O ₃ , 0.02 μm
Each of Y ₂ O ₃ and 0.02 μm Ce ₂ O ₃ starting material powders was weighed to the composition shown in Table 2 and inserted into a stainless steel pot together with an acetone solvent and a cemented carbide ball. After mixing and grinding for 48 hours, the mixture was dried to obtain a mixed powder.

The mixed powder is filled in a mold, and 2 to
Approximately 5.5 x 9.5 x 29 mm with a pressure of n / cm ²
Is prepared and placed on a sheet made of alumina and carbon fiber, and in a vacuum at an atmospheric pressure of 10 Pa,
By heating and holding at the temperatures shown in Table 2 for 1 hour, inventive products 1 to 9 and comparative products 1 to 9 were obtained.

The cemented carbides of the present invention products 1 to 9 and comparative products 1 to 9 thus obtained were wet-ground with a # 230 diamond grindstone to form a 4.0 × 8.0 × 25.0 mm shape. The bending force was measured by the JIS method, and the results are shown in Table 3. After lapping one surface of each sample of the same shape with a 0.3 μm diamond paste, the hardness and fracture toughness K _1c (IM method) at a load of 196 N using a Vickers indenter were measured. Are also shown in Table 3.

Further, a photograph of the structure of the lap surface of each sample having the same shape was taken with an electron microscope, and the volume ratio of the binder phase, the cubic compound phase, the oxide phase, the total WC and the average of the WC were measured with an image processing apparatus. The particle size and the volume ratio of the plate-like WC crystal (the longest diameter / the shortest diameter was 3 or more) to the total WC were determined, and the results are also shown in Table 4. In addition, oxide particles and other substances (metal particles) which are intragranular dispersions dispersed in the WC crystal
Was measured for the composition, particle size and volume ratio to the total WC.
It was shown to.

These inventive products 1 to 9 and comparative products 1 to
9, SNGN according to the invention product 1 and the comparison product 1
A 120408-shaped cutting tool chip was produced. Using this cutting tool tip, a work material: chilled roll (H
RC = 60), Cutting speed: 15m / min, Depth of cut:
A dry turning test was performed under the conditions of 1.5 mm, feed: 0.3 mm / rev, and the life time until chipping, chipping, or average flank wear width became 0.45 mm was determined. As a result, the product 1 of the present invention was 25 minutes while the product 1 of the comparative example was 19 minutes.

Next, products 3 and 7 of the present invention and comparative products 3 and
The cemented carbide material No. 7 was ground using a 230 # diamond grindstone to produce a cutting tool chip of SPGN120308. Using the cutting tool tip thus obtained, a work material: FC350, a cutting speed: 100 m / mi
n, depth of cut: 1.5 mm, feed: 0.3 mm / rev,
Cutting Time: perform dry turning test under the conditions of 10min, to obtain an average flank wear width V _B. As a result, the product of the present invention 3,
Whereas 7 of V _B was 0.26mm and 0.24 mm, respectively comparative sample 3, 7 0.32 mm and 0.29m
m.

Further, the cemented carbide chip material of the product 6 of the present invention and the comparative product 6 were ground using a 230 # diamond grindstone to produce a cutting tool chip of SPGN120308. The work material: SC was obtained by using three cutting tool tips each made of a sample having the same composition and thus obtained.
M440, cutting speed: 100 m / min, cutting depth: 2.
A dry milling test was performed under the conditions of 0 mm, feed: 0.40 mm / blade, and cutting distance: 2 m. When chipping or chipping occurred on the cutting edge, or when the flank wear amount was 0.
The average cutting distance of three cutting tool tips until the number reached 25 was determined. As a result, the cuttable distance of the product 6 of the present invention is 9.
Compared to 8 m, comparative product 6 was 7.9 m.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

[Table 5]

[0040]

The WC-containing cemented carbide strengthened intragranularly by the oxide of the present invention has a higher transverse rupture strength, hardness and hardness than a conventional cemented carbide made of the same composition. Excellent in fracture toughness, especially excellent strength, toughness, thermal crack resistance and thermal shock resistance. As a result, it is necessary to emphasize strength, toughness, thermal crack resistance and thermal shock resistance. When used as a rotary cutting tool typified by a certain milling cutter and a gun drill, the tool life is remarkably improved.

Claims (15)

[Claims] 1. A binder phase comprising an iron group metal as a main component in an amount of 5 to 3
In a cemented carbide containing 5% by volume and a hard phase made of tungsten carbide, the hard phase is an intragranular dispersion strengthened tungsten carbide in which an intragranular dispersion containing an oxide is dispersed in the grains of the tungsten carbide. And the total content of the intragranular dispersion is 0.0% with respect to the entire tungsten carbide.
A WC-containing cemented carbide reinforced intragranularly by an oxide, which is 1% by volume or more. 2. The cemented carbide according to claim 1, wherein said cemented carbide is a carbide, carbonitride, carbonate, carbonitride or a mutual solid solution of metals of groups 4a, 5a and 6a of the periodic table. 55% by volume of a cubic compound phase composed of at least one of
The WC-containing cemented carbide reinforced by intragranular dispersion with the oxide according to claim 1, wherein the WC-containing cemented carbide is contained. 3. The cemented carbide according to claim 1, wherein said cemented carbide is Mg, Al, and a rare earth element (including Sc and Y).
3. The WC-containing cemented carbide in which particles are dispersed intragranularly by the oxide according to claim 1, wherein the WC-containing cemented carbide contains 5 vol% or less of a dispersed phase of an oxide composed of at least one of the following. 4. The method according to claim 1, wherein the intragranular dispersion is an oxide composed of at least one of Mg, Al, and rare earth elements (including Sc and Y). A WC-containing cemented carbide which is intragranular dispersion strengthened by the oxide according to 1. 5. The intragranular dispersion of an oxide according to claim 1, wherein the intragranular dispersion contains an oxide and a metal and / or an alloy. WC-containing cemented carbide. 6. The oxide comprises at least one of Mg, Al, and rare earth elements (including Sc and Y), and the metal and / or alloy comprises an iron group metal or an alloy thereof. A WC-containing cemented carbide reinforced by intragranular dispersion with the oxide according to claim 5. 7. The intragranular dispersion has an average diameter of 0.5 μm.
WC enhanced in intragranular dispersion by the oxide according to any one of claims 1 to 6, characterized in that:
Containing cemented carbide. 8. The above-mentioned intragranular dispersion strengthened tungsten carbide,
The WC-containing cemented carbide as set forth in any one of claims 1 to 7, wherein the WC-containing cemented carbide is made of plate-like crystal tungsten carbide and is strengthened by intragranular dispersion strengthening with an oxide. 9. The transgranular dispersion strengthened tungsten carbide,
9. The method according to claim 1, wherein the average particle diameter is 3 to 300 times the average diameter of the intragranular dispersion.
Item 7. A WC-containing cemented carbide which is intragranular dispersion strengthened by the oxide described in Item 8. 10. The oxide according to claim 1, wherein the tungsten carbide is strengthened by 20% by volume or more based on the whole tungsten carbide. WC-containing cemented carbide with intragranular dispersion strengthening. 11. A first step of mixing and pulverizing starting materials for producing a cemented carbide to form a mixed powder, a second step of molding the mixed powder to form a powder compact, and the powder compact. 1200-1600 ° C. in a non-oxidizing atmosphere or vacuum
And a third step of heating and sintering the cemented carbide, wherein the starting materials are a binder phase forming powder mainly composed of an iron group metal, W powder, carbon and / or graphite. A method for producing a WC-containing cemented carbide strengthened intragranularly by an oxide, comprising a carbon source powder of (1) and an oxide powder that is stable during the heat sintering. 12. The oxide powder is composed of Mg, Al, S
12. A WC-containing carbide hardened by intragranular dispersion strengthening by an oxide according to claim 11, wherein the oxide powder is an oxide powder comprising at least one of i and a rare earth element (including Sc and Y). Alloy manufacturing method. 13. A first step of mixing and pulverizing starting materials for producing a cemented carbide to form a mixed powder, a second step of forming the mixed powder into a powder compact, and the powder compact. From 1200 to 1600 in a non-oxidizing atmosphere or vacuum
A step of heating and sintering at a temperature of at least 2 ° C., wherein the starting material is a W-containing alloy powder comprising W and at least one metal for forming an oxide. A WC-containing cemented carbide strengthened intragranularly by an oxide, characterized by containing a binder phase forming powder mainly composed of an iron group metal and a carbon source powder of carbon and / or graphite. Manufacturing method. 14. The W-containing alloy powder, wherein W and Mg, A
14. The oxide of claim 13, which is an alloy powder comprising at least one of l, Si, and a rare earth element (including Sc and Y).
Manufacturing method of C-containing cemented carbide. 15. The starting material as described in claim 4 of the periodic table.
a, a, 5a, or 6a group metal carbide, nitride, oxide, carbonitride, carbonate, nitroxide, carbonitride, and a metal compound powder of at least one of these mutual solid solutions. A W-particle having intragranular dispersion strengthening by the oxide according to any one of claims 12 to 14.
Manufacturing method of C-containing cemented carbide.