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A method for preparing tungsten slabs by low-temperature sintering

A low-temperature sintering and tungsten slab technology, applied in the field of powder metallurgy, can solve the problems of large equipment loss, lower sintering temperature, and low density, and achieve the effects of good structure uniformity, reduced holding time, and high density

Active Publication Date: 2017-11-10
XIAN REFRA TUNGSTEN & MOLYBDENUM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, in the production process, not only the energy consumption is high and the equipment loss is large, but also the degree of surface densification and the depth of attachment increase with the increase of temperature, which easily leads to coarse grains and low density at the center of the large slab. Not conducive to the uniform deformation of the subsequent rolling process
Chinese Patent No. 200810222429.X discloses "a preparation method of tungsten billet for rolling plate". powder to achieve a higher filling effect. These two methods prepare high-density, high-uniformity sintered tungsten slabs. This method has a high sintering temperature and requires the sintering furnace to have a frequency conversion function, which requires high equipment; It is to achieve a denser filling effect, which does not help to reduce the sintering temperature

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] The preparation method of the present embodiment comprises the following steps:

[0020] Step 1. Put 25kg of tungsten powder with an average particle size of 1.0 μm, 70 kg of tungsten powder with an average particle size of 2.3 μm and 5 kg of tungsten powder with an average particle size of 3.0 μm into a V-type mixer for 6 hours to obtain mixed tungsten powder; The chemical composition of the tungsten powder is in line with the requirements of GB / T3458-2006FW-1;

[0021] Step 2. Press the mixed tungsten powder described in step 1 into a slab by cold isostatic pressing. The pressing pressure is 280 MPa, and the holding time is 3 minutes;

[0022] Step 3. Under a hydrogen atmosphere, heat and sinter the slab described in step 2, and obtain a tungsten slab after natural cooling; the specific process of heating and sintering is: first heat the slab to 1500° C. for 2 hours, and then Heating to 1700°C for 6 hours, and then heating to 2100°C for 10 hours; the time for the sla...

Embodiment 2

[0025] The preparation method of the present embodiment comprises the following steps:

[0026] Step 1. Put 15kg of tungsten powder with an average particle size of 1.2 μm, 75 kg of tungsten powder with an average particle size of 2.5 μm and 10 kg of tungsten powder with an average particle size of 3.5 μm into a V-type mixer for 3 hours to obtain mixed tungsten powder; The chemical composition of the tungsten powder is in line with the requirements of GB / T3458-2006FW-1;

[0027] Step 2. Press the mixed tungsten powder described in step 1 into a slab by cold isostatic pressing. The pressing pressure is 250 MPa, and the holding time is 2.5 minutes;

[0028] Step 3. Under a hydrogen atmosphere, heat and sinter the slab described in step 2, and obtain a tungsten slab after natural cooling; the specific process of heating and sintering is: first heat the slab to 1500°C for 3 hours, and then Heating to 1700°C for 10h and then heating to 2100°C for 20h; the time for heating the slab...

Embodiment 3

[0031] The preparation method of the present embodiment comprises the following steps:

[0032] Step 1. Put 20kg of tungsten powder with an average particle size of 0.8 μm, 65 kg of tungsten powder with an average particle size of 2.4 μm and 15 kg of tungsten powder with an average particle size of 3.2 μm in a V-type mixer for 5 hours to obtain mixed tungsten powder; The chemical composition of the tungsten powder is in line with the requirements of GB / T3458-2006FW-1;

[0033] Step 2. Press the mixed tungsten powder described in step 1 into a slab by cold isostatic pressing. The pressing pressure is 260 MPa, and the holding time is 2 minutes;

[0034] Step 3. Under a hydrogen atmosphere, heat and sinter the slab described in step 2, and obtain a tungsten slab after natural cooling; the specific process of heating and sintering is as follows: first heat the slab to 1500° C. for 1 hour, and then Heating to 1700°C for 8 hours, and then heating to 2100°C for 12 hours; the time fo...

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Abstract

The invention discloses a method for preparing a tungsten slab by low-temperature sintering. The method includes: first, preparing mixed tungsten powder; second, pressing the mixed tungsten powder into a slab by cold isostatic pressing; third, in a hydrogen atmosphere, The slab is heated and sintered, and the tungsten slab is obtained after natural cooling. The present invention mixes the tungsten powders of three particle size ranges uniformly in proportion, on the one hand, it achieves good filling property, obtains a higher compact density and then obtains a higher sintered density; In addition, by controlling the temperature and time of slab sintering, it can be avoided that the surface densification speed of the sintered blank is much faster than that of the core due to the excessively fast heating speed or the short holding time in the medium and low temperature stage. Therefore, it will cause the phenomenon that the pores in the core of the sintered slab are difficult to eliminate, and ensure that each part of the slab has good organizational uniformity and high density.

Description

technical field [0001] The invention belongs to the technical field of powder metallurgy, and in particular relates to a method for preparing a tungsten slab by low-temperature sintering. Background technique [0002] The high melting point of tungsten makes it have extremely high heat resistance, and it is an important structural material and heating component of ultra-high temperature furnaces. At the same time, tungsten also has a strong ability to absorb rays, and tungsten plates will play a huge role in the development of the nuclear energy industry. In addition, tungsten plates are also widely used in ion sputtering, ion implantation, and coating industries. The basic preparation process of powder metallurgy tungsten slab is: mixing, pressing and sintering. In order to pursue high density and better structure uniformity, the sintering temperature of traditional tungsten slabs will reach about 2300°C, and the holding time is usually more than 10 hours. Therefore, in ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F1/00B22F3/10
CPCB22F3/1017B22F2998/10B22F2999/00B22F1/052B22F2201/013B22F3/04
Inventor 李长亮任吉文林三元王喆姬毓金波
Owner XIAN REFRA TUNGSTEN & MOLYBDENUM
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