Method for preparing tungsten slab by low-temperature sintering

Abstract

The invention discloses a method for preparing a tungsten slab by low-temperature sintering. The method comprises the following steps: (1) mixed tungsten powder is prepared; (2) the mixed tungsten powder is pressed to a slab by a cold isostatic pressing mode; and (3) under hydrogen atmosphere, the slab is heated and sintered, and is naturally cooled to obtain the tungsten slab. The method uniformly mixes the tungsten powder with three particle size ranges in proportion; on the one hand, excellent filling capacity is realized, higher pressing blank density is obtained, and higher sintering density is obtained; and on the other hand, quick actuation of densification process at a lower temperature is guaranteed, and the highest sintering temperature and insulation time are reduced; and in addition, through controlling the slab sintering temperature and time, the phenomenon of difficult elimination of a core hole of the sintered slab caused by the surface dentification speed of the sintered slab far faster than the core dentification speed due to excessive fast heating speed or shorter insulation time in medium-low-temperature phase can be prevented, and each part of the slab has better structure uniformity and higher 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 ...

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