CN112176238B - Ultra-fine grain hard alloy and preparation method thereof - Google Patents
Ultra-fine grain hard alloy and preparation method thereof Download PDFInfo
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- 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
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- C22C1/051—Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
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- 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
- C22C29/067—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 comprising a particular metallic binder
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Abstract
The invention provides an ultrafine grain hard alloy which is prepared from the following components in percentage by weight: 8-12% of Co, 0.6-1% of inhibitor and the balance of WC, wherein the sum of the weight percentages of the components is 100%. The invention also provides a preparation method of the ultrafine grained hard alloy. The ultrafine grain hard alloy provided by the invention uses an inhibitor which can effectively inhibit the growth of crystal grains, and has better mechanical properties.
Description
Technical Field
The invention relates to a hard alloy, in particular to an ultra-fine grain hard alloy and a preparation method thereof.
Background
The ultra-fine grain cemented carbide has high hardness and high strength, which are one of the hot spots developed in the industry, but in the process of manufacturing the ultra-fine cemented carbide, the activity of the used WC powder is much higher than that of the general WC powder, so that the phenomenon of abnormal growth of crystal grains occurs in the sintering process, the structure is not uniform, and the performance of the product is adversely affected. The inhibitor is one of the important ways for preparing the ultrafine hard alloy, and the main functions of adding the inhibitor are as follows: firstly, inhibiting the growth of tungsten carbide crystal grains, and reducing the sensitivity of the alloy to sintering temperature and time; secondly, a two-phase region of the YG alloy is enlarged, and the influence of the change of the carbon content on the performance of the alloy is reduced; phase composition is changed, and alloy performance is improved; and fourthly, improving the heat resistance and the crater wear resistance of the alloy. However, when the addition amount of the inhibitor is small, the inhibitor is difficult to be uniformly mixed in the ball milling process, and the abnormal growth of crystal grains still occurs during sintering; when the addition amount of the inhibitor is large, the inhibitor can hinder the densification process of alloy sintering, so that the mechanical property of the alloy is poor.
Chinese patent application CN201710949306.5 discloses 'a WC-10Co ultrafine grain hard alloy cutter prepared by pretreating composite powder', which comprises the following preparation raw materials: WO2.9 powder having a purity of 99.5% and an average particle diameter of 0.2 μm, Co3O4 powder having a purity of 98.5% and an average particle diameter of 0.8 μm, and carbon black having a purity of 99.8% and an ash mass fraction of less than 0.1%. The preparation steps are as follows: the raw materials are mixed according to an experimental design scheme, a certain amount of 0.2% VC-0.8% Cr3C2 of a grain growth inhibitor is added, in-situ reduction carbonization reaction is utilized to prepare ultra-fine grain WC-10Co composite powder, the prepared composite powder is put into a vacuum furnace for pretreatment, then the composite powder is subjected to compression molding, and sintering is carried out in a low-pressure sintering furnace. The invention has the following problems: the used crystal grain growth inhibitor can not be uniformly distributed in an alloy system, and the effect of inhibiting abnormal growth of crystal grains is poor, so that the performance of the alloy cutter is not ideal.
Disclosure of Invention
The invention aims to provide an ultrafine grained hard alloy which uses an inhibitor capable of effectively inhibiting grain growth and has better mechanical property.
In order to solve the technical problems, the technical scheme of the invention is as follows:
the ultra-fine grain hard alloy is prepared from the following components in percentage by weight: 8-12% of Co, 0.6-1% of inhibitor and the balance of WC, wherein the sum of the weight percentages of the components is 100%.
Furthermore, the average particle size of Co is 100-200 nm.
Further, the inhibitor of the invention is prepared by the following steps:
A1. adding ammonium niobate into water, uniformly mixing to obtain an ammonium niobate solution, adding ammonium tantalate into water, uniformly mixing to obtain an ammonium tantalate solution, adding oxalic acid into water, uniformly mixing to obtain an oxalic acid solution, mixing the ammonium niobate solution, the ammonium tantalate solution and the oxalic acid solution, stirring until a precipitate is generated, standing for 4 hours, taking out the precipitate, washing for 3 times with deionized water after filtering, freeze-drying for 10 hours to obtain a precursor, adding the precursor into a tubular furnace, and calcining for 5 hours at 500 ℃ under nitrogen atmosphere to obtain a niobium-tantalum composite oxide;
A2. uniformly mixing niobium-tantalum composite oxide and carbon powder to obtain mixed powder, placing the mixed powder in a vacuum carbon tube furnace, introducing argon to protect the mixed powder, heating the mixed powder to 1000 ℃, preserving the heat for 2 hours, cooling the mixed powder along with the furnace to room temperature, taking out the mixed powder, and grinding the mixed powder to obtain the inhibitor with the average particle size of 100-200 nm.
Further, in the step A1 of the present invention, the concentration of the ammonium niobate solution is 0.2mol/L, the concentration of the ammonium tantalate solution is 0.2mol/L, the concentration of the oxalic acid solution is 0.2mol/L, and the volume ratio of the ammonium niobate solution, the ammonium tantalate solution, and the oxalic acid solution is 1:0.2: 1.5.
Further, in the step a2 of the present invention, the weight ratio of the niobium tantalum composite oxide to the carbon powder is 3:1, and the vacuum degree of the vacuum carbon tube furnace is 0.03 Pa.
Further, the average grain size of the WC is 100-200 nm.
Another technical problem to be solved by the present invention is to provide a method for preparing the above ultra-fine grained cemented carbide.
In order to solve the technical problems, the technical scheme is as follows:
a preparation method of ultra-fine grain hard alloy comprises the following steps:
B1. weighing the components according to the weight percentage, adding the components and a ball milling medium into a ball mill, performing ball milling for 36-48 hours to obtain a mixture, performing vacuum drying on the mixture, and sieving with an 80-mesh sieve for granulation to obtain mixed granules;
B2. placing the mixed granules in a die cavity to be molded into a pressed blank;
B3. and (3) placing the pressed compact in a sintering furnace, introducing argon into the vacuum sintering furnace until the pressure is 5-6 Mpa, heating to 1200-1300 ℃, preserving heat for 1-2 hours, then heating to 1400-1450 ℃, preserving heat for 0.5-1 hour, and cooling to room temperature along with the furnace to obtain the ultrafine grain hard alloy.
In step B1, the ball-to-material ratio during ball milling is (5-6): 1, the rotation speed of the ball mill is 200-300 r/m, and the ball milling medium is sodium carboxymethylcellulose.
Further, in the step B2, the mould pressing pressure is 150-200 MPa.
Further, in step B3 of the present invention, the temperature increase rate was 5 ℃/min.
Compared with the prior art, the invention has the following beneficial effects:
1) according to the invention, ammonium niobate, ammonium tantalate and oxalic acid are used as raw materials to prepare niobium-tantalum composite oxide through a coprecipitation method, then the niobium-tantalum composite oxide and carbon are subjected to reduction reaction to prepare the inhibitor with a niobium carbide-tantalum carbide composite structure, niobium carbide in the inhibitor has the effect of inhibiting abnormal growth of crystal grains, but the niobium carbide in the inhibitor cannot be uniformly distributed in a hard alloy system when used alone, and tantalum carbide in the inhibitor prepared by the invention can improve the distribution uniformity of the niobium carbide in the hard alloy system, so that the effect of inhibiting abnormal growth of the crystal grains of the niobium carbide is fully exerted, WC crystal grains are refined, and the mechanical properties of hardness, bending strength and the like of the grown hard alloy are improved; in addition, tantalum carbide also improves the fracture toughness of the cemented carbide.
2) According to the invention, sodium carboxymethylcellulose is used as a ball milling medium, so that the dispersion uniformity of each component during ball milling can be improved, and agglomeration is avoided, thereby improving the fracture toughness and the density of the hard alloy.
Detailed Description
The present invention will be described in detail with reference to specific embodiments, and the exemplary embodiments and descriptions thereof herein are provided to explain the present invention but not to limit the present invention.
Example 1
The ultra-fine grain hard alloy is prepared from the following components in percentage by weight: co 10% with the average particle size of 100-200 nm, 1% of inhibitor and the balance of WC with the average particle size of 100-200 nm, wherein the sum of the weight percentages of the components is 100%.
The inhibitor is prepared by the following steps:
A1. adding ammonium niobate into water, uniformly mixing to obtain an ammonium niobate solution with the concentration of 0.2mol/L, adding ammonium tantalate into water, uniformly mixing to obtain an ammonium tantalate solution with the concentration of 0.2mol/L, adding oxalic acid into water, uniformly mixing to obtain an oxalic acid solution with the concentration of 0.2mol/L, mixing the ammonium niobate solution, the ammonium tantalate solution and the oxalic acid solution with the volume ratio of 1:0.2:1.5, stirring to generate a precipitate, standing for 4 hours, taking out the precipitate, filtering, washing with deionized water for 3 times, freeze-drying for 10 hours to obtain a precursor, adding the precursor into a tubular furnace, and calcining for 5 hours at 500 ℃ in a nitrogen atmosphere to obtain a niobium-tantalum composite oxide;
A2. uniformly mixing niobium-tantalum composite oxide and carbon powder in a weight ratio of 3:1 to obtain mixed powder, placing the mixed powder in a vacuum carbon tube furnace with the vacuum degree of 0.03Pa, introducing argon to protect the temperature of the furnace, raising the temperature to 1000 ℃, preserving the temperature for 2 hours, cooling the furnace to room temperature, taking out the furnace, and grinding the furnace to obtain the inhibitor with the average particle size of 100-200 nm.
The preparation method of the ultrafine grain hard alloy comprises the following steps:
B1. weighing the components according to the weight percentage, adding the components and sodium carboxymethylcellulose into a ball mill for ball milling for 42 hours to obtain a mixture, carrying out vacuum drying on the mixture, and then sieving through a 80-mesh sieve for granulation to obtain mixed granules, wherein the ball-material ratio is 5:1 during ball milling, and the rotating speed of the ball mill is 200 revolutions per minute;
B2. placing the mixed granules in a die cavity of a die and pressing under 180Mpa of die pressing pressure to form a green compact;
B3. and placing the pressed compact in a sintering furnace, introducing argon into the vacuum sintering furnace until the pressure is 6Mpa, heating to 1250 ℃ at the heating rate of 5 ℃/min, then preserving heat for 1.5 hours, heating to 1420 ℃ at the heating rate of 5 ℃/min, preserving heat for 0.8 hours, and cooling to room temperature along with the furnace to obtain the ultrafine crystal hard alloy.
Example 2
The ultra-fine grain hard alloy is prepared from the following components in percentage by weight: co 9 with the average particle size of 100-200 nm, 0.9 percent of inhibitor and the balance of WC with the average particle size of 100-200 nm, wherein the sum of the weight percentages of the components is 100 percent.
The procedure for the preparation of the inhibitor was the same as in example 1.
The preparation method of the ultrafine grain hard alloy comprises the following steps:
B1. weighing the components according to the weight percentage, adding the components and sodium carboxymethylcellulose into a ball mill, carrying out ball milling for 36 hours to obtain a mixture, carrying out vacuum drying on the mixture, sieving the mixture through a 80-mesh sieve, and carrying out granulation to obtain mixed granules, wherein the ball-material ratio is 6:1 during ball milling, and the rotating speed of the ball mill is 300 r/min;
B2. placing the mixed granules in a die cavity of a die and pressing under the die pressing pressure of 200Mpa to form a pressed blank;
B3. placing the pressed compact in a sintering furnace, introducing argon into the vacuum sintering furnace until the pressure is 5Mpa, heating to 1200 ℃ at the heating rate of 5 ℃/min, then preserving heat for 2 hours, then heating to 1400 ℃ at the heating rate of 5 ℃/min, preserving heat for 1 hour, and cooling to room temperature along with the furnace to obtain the ultrafine grain hard alloy.
Example 3
The ultra-fine grain hard alloy is prepared from the following components in percentage by weight: co 8% with the average particle size of 100-200 nm, 0.8% of inhibitor and the balance of WC with the average particle size of 100-200 nm, wherein the sum of the weight percentages of the components is 100%.
The procedure for the preparation of the inhibitor was the same as in example 1.
The preparation method of the ultrafine grain hard alloy comprises the following steps:
B1. weighing the components according to the weight percentage, adding the components and sodium carboxymethylcellulose into a ball mill for ball milling for 48 hours to obtain a mixture, carrying out vacuum drying on the mixture, sieving the mixture through a 80-mesh sieve for granulation to obtain mixed granules, wherein the ball-material ratio is 6:1 during ball milling, and the rotating speed of the ball mill is 300 r/min;
B2. placing the mixed granules in a die cavity of a die, and pressing under the die pressing pressure of 150Mpa to form a pressed blank;
B3. and placing the pressed compact in a sintering furnace, introducing argon into the vacuum sintering furnace until the pressure is 6Mpa, heating to 1300 ℃ at the heating rate of 5 ℃/min, then preserving heat for 1 hour, heating to 1450 ℃ at the heating rate of 5 ℃/min, preserving heat for 0.5 hour, and cooling to room temperature along with the furnace to obtain the ultrafine grain hard alloy.
Example 4
The ultra-fine grain hard alloy is prepared from the following components in percentage by weight: co 12 with the average particle size of 100-200 nm, 0.6 percent of inhibitor and the balance of WC with the average particle size of 100-200 nm, wherein the sum of the weight percentages of the components is 100 percent.
The procedure for the preparation of the inhibitor was the same as in example 1.
The preparation method of the ultrafine grain hard alloy comprises the following steps:
B1. weighing the components according to the weight percentage, adding the components and sodium carboxymethylcellulose into a ball mill for ball milling for 40 hours to obtain a mixture, carrying out vacuum drying on the mixture, sieving the mixture through a 80-mesh sieve for granulation to obtain mixed granules, wherein the ball-material ratio is 5:1 during ball milling, and the rotating speed of the ball mill is 200 revolutions per minute;
B2. placing the mixed granules in a die cavity of a die under 160Mpa die pressing pressure to be pressed into a green compact;
B3. and placing the pressed compact in a sintering furnace, introducing argon into the vacuum sintering furnace until the pressure is 5Mpa, heating to 1280 ℃ at the heating rate of 5 ℃/min, then preserving heat for 1.2 hours, then heating to 1440 ℃ at the heating rate of 5 ℃/min, preserving heat for 0.6 hours, and cooling to room temperature along with the furnace to obtain the ultrafine grain hard alloy.
Reference example 1:
the difference from example 1 is that: the inhibitor in the components is replaced by niobium carbide, and the preparation step of the inhibitor is omitted. Reference example 2:
the difference from example 1 is that: the inhibitor in the components is directly mixed by niobium carbide and tantalum carbide with the molar ratio of 5:1, and the preparation step of the inhibitor is omitted.
Reference example 3:
the difference from example 1 is that: sodium carboxymethylcellulose was not used in step B1.
Comparative example: embodiment one of chinese patent application No. CN 201710949306.5.
The first test example: hardness test
The test method comprises the following steps: vickers hardnesses of examples 1 to 4, reference examples 1 to 3, and comparative example were measured using a Brookfield hardness tester, respectively, with a load of 980N and a dwell time of 15 seconds. The test results are shown in table 1:
TABLE 1
As can be seen from Table 1, the Vickers hardness of the inventive examples 1-4 is significantly higher than that of the comparative examples, indicating that the inventive examples have higher hardness. The components or preparation steps of reference examples 1-3 are different from those of reference example 1, the vickers hardness of reference example 1 is obviously reduced, and the tantalum carbide in the inhibitor used in the invention can effectively improve the distribution uniformity of niobium carbide in the hard alloy; the decrease of vickers hardness of reference example 2 is smaller than that of reference example 1, which shows that the treatment method of niobium carbide and tantalum carbide according to the present invention has a better effect of improving the distribution uniformity of niobium carbide in cemented carbide than that of directly mixing niobium carbide and tantalum carbide.
Test example two: bending strength test
The test method comprises the following steps: the bending strengths of examples 1 to 4, reference examples 1 to 3 and comparative example were measured by three-point bending test using a universal mechanical tester, and the test results are shown in table 2:
| bending strength (MPa) | |
| Example 1 | 3860 |
| Example 2 | 3750 |
| Example 3 | 3690 |
| Example 4 | 3810 |
| Reference example 1 | 3370 |
| Reference example 2 | 3530 |
| Reference example 3 | 3850 |
| Comparative example | 2980 |
TABLE 2
As can be seen from Table 2, the flexural strength of the inventive examples 1-4 is significantly higher than that of the comparative examples, indicating that the inventive compositions have higher flexural strength. The parts of the components or preparation steps of the reference examples 1-3 are different from those of the reference example 1, the bending strength of the reference example 1 is obviously reduced, and the tantalum carbide in the inhibitor used in the invention can effectively improve the distribution uniformity of the niobium carbide in the hard alloy; the reduction degree of the bending strength of the reference example 2 is smaller than that of the reference example 1, which shows that compared with the direct mixing of niobium carbide and tantalum carbide, the treatment method of the invention for niobium carbide and tantalum carbide has better effect on improving the distribution uniformity of niobium carbide in the hard alloy.
Test example three: fracture toughness test
The test method comprises the following steps: the fracture toughness of examples 1 to 4, reference examples 1 to 3, and comparative example were measured by the indentation method, respectively, and the calculation formula was: k is 0.0028 × (HV × P/Σ L)1/2Wherein K is fracture toughness in Mpa m1/2(ii) a HV is the Vickers hardness value at a load of P, in N/mm2(ii) a Σ L is the sum of the lengths of the four cracks at the top corners of the indentation, in mm. The test results are shown in table 3:
| fracture toughness (Mpa. m)1/2) | |
| Example 1 | 12.6 |
| Example 2 | 12.0 |
| Example 3 | 11.8 |
| Example 4 | 12.3 |
| Reference example 1 | 10.7 |
| Reference example 2 | 12.6 |
| Reference example 3 | 10.3 |
| Comparative example | 12.6 |
TABLE 3
As can be seen from Table 3, the fracture toughness of the inventive examples 1-4 is significantly higher than that of the comparative examples, indicating that the inventive examples have higher fracture toughness. The components or preparation steps of reference examples 1-3 are different from those of reference example 1, the fracture toughness of reference examples 1 and 3 are obviously reduced, and the tantalum carbide in the inhibitor used in the invention and the sodium carboxymethyl cellulose used in step B1 of the preparation method are both effective in improving the fracture toughness of the hard alloy.
Test example four: grain size test
The test method comprises the following steps: the microstructures of examples 1 to 4, reference examples 1 to 3, and comparative example were observed using a scanning electron microscope, respectively, and 100 crystal grain sizes were randomly measured by Image-Rro software, and the average crystal grain size was calculated to characterize the crystal grain size, and the test results are shown in table 4:
TABLE 4
As can be seen from Table 4, the average grain sizes of inventive examples 1-4 are significantly smaller than those of comparative examples, indicating that the inventive compositions have smaller grain sizes. The components or preparation steps of reference examples 1-3 are different from those of reference example 1, the average grain size of reference example 1 is obviously increased, and the tantalum carbide in the inhibitor used in the invention can effectively improve the distribution uniformity of niobium carbide in the hard alloy; the average grain size of reference example 2 is increased to a smaller extent than that of reference example 1, which shows that the treatment method of the present invention for niobium carbide and tantalum carbide has a better effect of improving the distribution uniformity of niobium carbide in cemented carbide than that of directly mixing niobium carbide and tantalum carbide.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (9)
1. An ultra-fine grain cemented carbide, characterized in that: the paint is prepared from the following components in percentage by weight: 8-12% of Co, 0.6-1% of inhibitor and the balance of WC, wherein the sum of the weight percentages of the components is 100%;
the inhibitor is prepared by the following steps:
A1. adding ammonium niobate into water, uniformly mixing to obtain an ammonium niobate solution, adding ammonium tantalate into water, uniformly mixing to obtain an ammonium tantalate solution, adding oxalic acid into water, uniformly mixing to obtain an oxalic acid solution, mixing the ammonium niobate solution, the ammonium tantalate solution and the oxalic acid solution, stirring until a precipitate is generated, standing for 4 hours, taking out the precipitate, washing for 3 times with deionized water after filtering, freeze-drying for 10 hours to obtain a precursor, adding the precursor into a tubular furnace, and calcining for 5 hours at 500 ℃ under nitrogen atmosphere to obtain a niobium-tantalum composite oxide;
A2. uniformly mixing niobium-tantalum composite oxide and carbon powder to obtain mixed powder, placing the mixed powder in a vacuum carbon tube furnace, introducing argon to protect the mixed powder, heating the mixed powder to 1000 ℃, preserving the heat for 2 hours, cooling the mixed powder along with the furnace to room temperature, taking out the mixed powder, and grinding the mixed powder to obtain the inhibitor with the average particle size of 100-200 nm.
2. The ultra-fine grained cemented carbide according to claim 1, characterized in that: the average particle size of Co is 100-200 nm.
3. The ultra-fine grained cemented carbide according to claim 1, characterized in that: in the step A1, the concentration of the ammonium niobate solution is 0.2mol/L, the concentration of the ammonium tantalate solution is 0.2mol/L, the concentration of the oxalic acid solution is 0.2mol/L, and the volume ratio of the ammonium niobate solution to the ammonium tantalate solution to the oxalic acid solution is 1:0.2: 1.5.
4. The ultra-fine grained cemented carbide according to claim 1, characterized in that: in the step A2, the weight ratio of the niobium-tantalum composite oxide to the carbon powder is 3:1, and the vacuum degree of the vacuum carbon tube furnace is 0.03 Pa.
5. The ultra-fine grained cemented carbide according to claim 1, characterized in that: the average particle size of WC is 100-200 nm.
6. The method for preparing an ultra-fine grained cemented carbide according to any one of claims 1 to 5, characterized in that: the method comprises the following steps:
B1. weighing the components according to the weight percentage, adding the components and a ball milling medium into a ball mill, performing ball milling for 36-48 hours to obtain a mixture, performing vacuum drying on the mixture, and sieving with an 80-mesh sieve for granulation to obtain mixed granules;
B2. placing the mixed granules in a die cavity to be molded into a pressed blank;
B3. and (3) placing the pressed compact in a sintering furnace, introducing argon into the vacuum sintering furnace until the pressure is 5-6 Mpa, heating to 1200-1300 ℃, preserving heat for 1-2 hours, then heating to 1400-1450 ℃, preserving heat for 0.5-1 hour, and cooling to room temperature along with the furnace to obtain the ultrafine grain hard alloy.
7. The method for preparing ultra-fine grain cemented carbide as claimed in claim 6, wherein: in the step B1, the ball-material ratio during ball milling is (5-6): 1, the rotation speed of the ball mill is 200-300 r/m, and the ball milling medium is sodium carboxymethylcellulose.
8. The method for preparing ultra-fine grain cemented carbide as claimed in claim 6, wherein: in the step B2, the mould pressing pressure is 150-200 Mpa.
9. The method for preparing ultra-fine grain cemented carbide as claimed in claim 6, wherein: in the step B3, the temperature rise rate is 5 ℃/min.
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| JPS62218531A (en) * | 1986-03-19 | 1987-09-25 | Mitsubishi Metal Corp | Manufacture of tungsten carbide-base sintered hard alloy |
| CN1480546A (en) * | 2003-07-22 | 2004-03-10 | 株洲硬质合金集团有限公司 | Method for preparing superfine hard alloy |
| CN106636834A (en) * | 2016-10-24 | 2017-05-10 | 湖南大学 | Method for inhibiting cemented carbide grain growth and ultra-fine grain cemented carbide preparation process |
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2020
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS55161046A (en) * | 1979-06-05 | 1980-12-15 | Nippon Oil & Fats Co Ltd | High density phase boron nitride-containing sintered body and its manufacture |
| JPS62218531A (en) * | 1986-03-19 | 1987-09-25 | Mitsubishi Metal Corp | Manufacture of tungsten carbide-base sintered hard alloy |
| CN1480546A (en) * | 2003-07-22 | 2004-03-10 | 株洲硬质合金集团有限公司 | Method for preparing superfine hard alloy |
| CN106636834A (en) * | 2016-10-24 | 2017-05-10 | 湖南大学 | Method for inhibiting cemented carbide grain growth and ultra-fine grain cemented carbide preparation process |
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