Ultrafine grain wolfram carbide/ cobalt hard alloy and preparation method thereof

A cemented carbide and tungsten carbide technology, which is applied in the field of ultrafine-grained tungsten carbide/cobalt-based cemented carbide and its preparation, can solve the problem of uneven grain size distribution of WC, inability to realize industrial production, and abnormal growth of grains, etc. problems, to achieve the effects of inhibiting grain growth, improving bonding performance, and reasonable component ratio

Active Publication Date: 2010-09-08
昆山长鹰硬质材料科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The growth of WC particles can be suppressed by means of external force and auxiliary external field, but these methods have the disadvantages of complex production process and high cost, and cannot realize industrial production
Another way to control the growth of ultrafine WC particles is by adding grain inhibi

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0031] Example 1

[0032] The preparation composition is WC-10Co-1LaB 6 -0.35Cr 3 C 2 -0.25VC (mass fraction, the same below) ultra-fine grained tungsten carbide / cobalt carbide. The raw materials used are 0.15um tungsten carbide powder, 1um cobalt powder, 2.5um vanadium carbide powder, 2.5um chromium carbide powder, and 3.5um lanthanum hexaboride powder. Weigh the raw material powder according to the alloy ratio, add polyethylene glycol forming agent, pass through argon protection, ball mill at 350 rpm for 48 hours on a ball mill, pass through a -100 mesh sieve, and then mold at room temperature with a pressure of 200 MPa forming. The compacts were degreased in a 400°C hydrogen furnace. Then it was sintered in a high temperature and low pressure sintering furnace, the sintering pressure was 5MPa, the sintering temperature was 1450℃, and the sintering time was 1h. The density of the sintered body is 98%, and the fracture toughness is 15MPa m. 1 / 2 .

Example Embodiment

[0033] Example 2

[0034] The preparation composition is WC-10Co-0.5CeB 6 -0.1Cr 3 C 2 -0.4VC (mass fraction, the same below) ultra-fine-grained tungsten carbide / cobalt cemented carbide. The raw materials used are 0.2um tungsten carbide powder, 1.5um cobalt powder, 5um vanadium carbide powder, 5um chromium carbide powder, and 5um cerium hexaboride powder. Weigh the raw material powder according to the alloy ratio, add polyethylene glycol forming agent, pass through a ball mill at a speed of 250 r / min for 48 hours under argon protection, pass through a -100 mesh sieve, and then mold at room temperature with a pressure of 300 MPa forming. The compacts were degreased in a 600°C hydrogen furnace. Then it was sintered in a high temperature and low pressure sintering furnace, the sintering pressure was 1MPa, the sintering temperature was 1500°C, and the sintering time was 4h. The density of the sintered body is 96%, and the fracture toughness is 13.2MPa m. 1 / 2 .

Example Embodiment

[0035] Example 3

[0036] The preparation composition is WC-5Co-2NdB 6 -0.6Cr 3 C 2 -0.1VC (mass fraction, the same below) ultra-fine grained tungsten carbide / cobalt cemented carbide. The raw materials used are 0.2um tungsten carbide powder, 1.0um cobalt powder, 3um vanadium carbide powder, 3um chromium carbide powder, and 3.5um neodymium hexaboride powder. Weigh the raw material powder according to the alloy ratio, add paraffin forming agent, pass through a ball mill at a speed of 400 rpm for 70 hours under argon protection, pass through a -100 mesh sieve, and then mold at room temperature with a pressure of 400 MPa. The compacts were degreased in a 500°C hydrogen furnace. Then sintered in a high temperature and low pressure sintering furnace, the sintering pressure is 2.5MPa, the sintering temperature is 1400°C, and the sintering time is 2.5h, the obtained ultrafine-grained tungsten carbide / cobalt cemented carbide WC has an average grain size of 341nm and a hardness of 9...

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Abstract

The invention discloses an ultrafine grain wolfram carbide (WC)/ cobalt hard alloy containing rare-earth hexaboride and a preparation method thereof and belongs to the field of high-performance powder metallurgy materials. The hard alloy comprises the following components in percentage by weight: 0.1 to 2 percent of the rare-earth hexaboride, 0.1 to 0.6 percent of chromium carbide, 0.1 to 0.4 percent of vanadium carbide, 5 to 15 percent of cobalt powder, and the balance of wolfram carbide powder. The preparation method comprises the following steps of: weighing the wolfram carbide powder, the cobalt powder, the rare-earth hexaboride powder, the chromium carbide powder and the vanadium carbide powder with certain granularity in percentage by weight; uniformly mixing the powder by ball milling; pressing the mixture by a mold pressing process to form a green ware body in a certain shape; degreasing the green ware body and sintering the degreased green ware body in a high-temperature low-pressure sintering furnace; and cooling the obtained product along with the furnace to obtain the ultrafine grain wolfram carbide/cobalt hard alloy. The hard alloy has the advantages of rational proportion of the components, simple production process, effective reduction in the grain size of the WC in the hard alloy and improvement on the hardness and fracture toughness of the hard alloy by adulterating the rare-earth hexaboride to inhibit the growth of the wolfram carbide grains in the sintered hard alloy, achievement of high hardness and fracture toughness and application in industrial production.

Description

technical field [0001] The invention discloses an ultra-fine-grained tungsten carbide / cobalt-based hard alloy and a preparation method thereof, in particular to an ultra-fine-grained tungsten carbide / cobalt-based hard alloy and a preparation method thereof. It belongs to the technical field of high-performance powder metallurgy materials. Background technique [0002] Tungsten carbide / cobalt-based cemented carbide is widely used as cutting tool and mold material due to its high hardness and high wear resistance. The strength and wear resistance of tungsten carbide / cobalt-based cemented carbide can be significantly improved by reducing the WC grain size in the alloy to the ultra-fine grain level (1um~300nm). However, in the traditional liquid phase pressureless sintering process, the ultrafine-grained WC particles are prone to abnormal growth. How to control the growth of WC has become one of the key technologies in the preparation of ultrafine-grained tungsten carbide / coba...

Claims

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Application Information

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IPC IPC(8): C22C29/08C22C1/05
Inventor 肖代红宋旼申婷婷欧小琴贺跃辉王守仁
Owner 昆山长鹰硬质材料科技股份有限公司
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