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Uniform macromeritic tungsten powder and method for preparing tungsten carbide powder

A coarse-grained, tungsten carbide technology, used in the field of refractory metal smelting, can solve the problems of many distorted grains, poor grain shape, and poor crystallization.

Active Publication Date: 2010-03-10
ZHUZHOU HARD ALLOY GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The preparation of coarse-grained tungsten carbide powder by high-temperature reduction and high-temperature carbonization method doped with alkali metal compounds has the following disadvantages: 1) coarse-grained tungsten powder has many defects, poor crystallization, and many distorted grains; In the process, the grains will be refined instead, which will easily cause high impurity content; 3) The grain morphology is not good and the uniformity is poor

Method used

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  • Uniform macromeritic tungsten powder and method for preparing tungsten carbide powder
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  • Uniform macromeritic tungsten powder and method for preparing tungsten carbide powder

Examples

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Effect test

Embodiment 1

[0016] Example 1: Use blue tungsten oxide powder with a Fsss particle size (the same below) of about 20 μm as raw material, with about 6 kg of raw material per boat. Raise the temperature of the reduction furnace to 1000°C, feed water vapor and hydrogen into the furnace, and control the P H20 / P H2 is 0.45. Then push into the material boat and reduce for about 15 hours. After discharge, sieve and remove scale to obtain coarse-grain tungsten powder with a Fsss particle size of about 21 μm. The morphology of the obtained coarse-grained tungsten powder is as attached figure 1 As shown, it can be seen that the crystal grains of tungsten powder particles are very coarse, relatively uniform, with very little fine powder, and good particle crystallization.

[0017] The obtained coarse-grained tungsten powder is carbonized according to a known method, with a carbon content of 6.15%, and then put into a carbonization furnace for carbonization. The carbonization temperature is 2300 °...

Embodiment 2

[0019] Embodiment 2: The coarse-grain tungsten powder obtained in Example 1 is mixed with carbon according to a known method, and the amount of carbon is 6.15%, and then put into a carbonization furnace for carbonization. The carbonization temperature is 2300 ° C, the carbonization time is 5 hours, and the carbonization atmosphere is Ar. After the furnace temperature drops to the temperature that can be released from the furnace, the material is discharged, and then processed in the same manner as in Example 1 to obtain coarse-grained tungsten carbide powder. The particle size of the obtained coarse-grained tungsten carbide powder is about 24 μm, and the appearance is similar to that attached figure 2 shown.

Embodiment 3

[0020] Example 3: Add tungsten powder with a weight ratio of about 5% and a particle size of about 3 μm into the blue tungsten oxide powder of about 20 μm, mix it for 1 to 2 hours and then load it into a boat, and each boat is filled with about 6Kg of the above mixed raw material . Raise the temperature of the reduction furnace to 1000°C, feed water vapor and hydrogen into the furnace, and control the P H20 / P H2is 0.5. Then push into the material boat and reduce for about 10 hours. After discharge, sieve and remove scale to obtain coarse-grained tungsten powder with a Fsss particle size of about 27 μm. The morphology of the obtained coarse-grained tungsten powder is as attached Figure 4 As shown, it can be seen that the crystal grains of the tungsten powder particles are coarser than that of Example 1, and also very uniform, with good crystallization.

[0021] The obtained coarse-grain tungsten powder is carbonized in the same manner as in Example 1, and the particle siz...

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Abstract

The invention discloses a uniform macromeritic tungsten powder and a method for preparing macromeritic tungsten carbide powder. During reduction, water vapor and hydrogen or a mixture thereof is sentinto a reducing furnace, and tungsten oxide powder materials or mixture materials of tungsten oxide powder and tungsten powder, which are pushed into the reducing furnace, are reduced to metallic tungsten powder by controlling the partial pressure ratio (PH2O / PH2) of the water vapor and the hydrogen sent into the reducing furnace and the temperature of the furnace. By the adjustment of technological parameters, macromeritic tungsten powder of multiple grades in the range of 10-100 micrometers can be prepared. The prepared macromeritic tungsten powder has the advantages of comparatively uniformgranularity, integrated crystallization, attractive appearance and high purity. After the carbonization of the macromeritic tungsten powder, uniform macromeritic tungsten carbide powder of 12-115 micrometers can be prepared. The invention can be used for producing macromeritic and super macromeritic hard alloy products of more than 4 micrometers and can be also used for the surface spray coating,the spray welding and the like of hard-surface materials.

Description

technical field [0001] The invention belongs to the refractory metal smelting technology, and relates to a preparation method of uniform coarse-grain tungsten powder and a method for preparing coarse-grain tungsten carbide powder by using the coarse-grain tungsten powder. Uniform coarse-grained tungsten powder and tungsten carbide powder are mainly used in the preparation of coarse-grained and ultra-coarse-grained hard alloys, the production of mining tools, stamping dies, drilling and mining tools, and can also be used in hard surface materials such as spraying and spray welding. Background technique [0002] Coarse-grained tungsten carbide is used in the production of cemented carbide because of its good crystallization properties, few structural defects, large sub-grain size, high microhardness, small microscopic strain, and certain plasticity. The fracture (impact) toughness of cemented carbide improves the service life and is widely used. Therefore, tungsten carbide po...

Claims

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Application Information

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IPC IPC(8): B22F9/22C01B31/34C01B32/949
Inventor 吴湘伟张忠键徐涛罗劲松陆必志皮志明谢晨辉
Owner ZHUZHOU HARD ALLOY GRP CO LTD
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