Method for preparing ultra-coarse-grain tungsten carbide from medium-particle tungsten powder

Abstract

The invention discloses a method for preparing ultra-coarse-grain tungsten carbide from medium-particle tungsten powder. The method comprises the steps of mixing treatment, pressing treatment, carbonization treatment, cooling and the like. The medium-particle tungsten powder is used as a raw material, and the ultra-coarse-grain tungsten carbide is prepared through a vacuum high-temperature catalytic carbonization method; under a high-temperature condition of 2200-2400 DEG C, metal cobalt liquid catalyzes and promotes the growth of tungsten carbide grains, and a tungsten carbide crystal is moreperfect; the ultra-coarse-grain tungsten carbide prepared through the method is complete in grain crystals and uniform in grain size; the problems of non-uniform carbon blending and generation of a tungsten carbide phase do not exist; coarse-particle tungsten powder does not need to be prepared, and the loss of reduction equipment is small; vacuum high-temperature carbonization is adopted, so theloss of a carbonization furnace is small; and the materials are formed by pressing, so the problem of boat sticking of the materials is avoided, and the recovery rate and yield of tungsten carbide are high.

Description

technical field [0001] The invention relates to the technical field of powder metallurgy material preparation, in particular to the technical field of ultra-coarse tungsten carbide and its preparation. Background technique [0002] Ultra-coarse-grained cemented carbide (grain size ≥ 5.0 μm) is an alloy material made of ultra-coarse-grained tungsten carbide and metal cobalt through powder metallurgy. Ultra-coarse-grained cemented carbide has extremely high thermal conductivity, excellent fracture toughness and red hardness, good thermal fatigue and thermal shock resistance, and is mainly used in extreme working conditions such as mining, road construction and mountain opening Die materials such as continuous excavation cutter head materials, stamping dies, cold heading dies, rolls, etc. [0003] Ultra-coarse-grained tungsten carbide is the key raw material for the preparation of coarse-grained cemented carbide due to its good crystallinity, few structural defects, large sub-...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: (1) The prepared coarse-grained tungsten carbide powder grains are difficult to grow thick and the grain size is uneven, which reduces the performance of coarse-grained cemented carbide

(2) Due to the large difference in particle size and specific gravity between tungsten powder and carbon black powder, the carbonization is uneven, so it is difficult to carbonize uniformly, and ditungsten carbide is easy to exist. (3) Since the reduction temperature is higher than 1000 ° C, The reduction equipment works in the limit state, and the equipment loss is large. If it is carbonized at 2000 °C or above under the hydrogen atmosphere, the carbonization equipment loss is large.

(4) Due to the high-temperature reduction and carbonization, the material sticks to the boat seriously, so that the yield and recovery rate of tungsten powder and tungsten carbide products are low

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