Research on Sintering Process of Coarse Grain Cemented Carbide

In the field of hard alloy, coarse grain cemented carbide has less structural defects, high hardness, low micro strain and a series of advantages, so it is widely used in rock drilling tools, drilling tools, stamping die, wear resistance and corrosion resistance, high temperature and high pressure parts, metal pressure processing tools, steel rolling, hard roll ring the field of materials etc..

During the sintering process of coarse grained cemented carbide, the main raw materials, coarse grain WC powder, all are doped with alkali metal ions Li, Na, K and other substances, which are used as particle growth agents to produce hydrogen at low temperature. With the raw material for the production of coarse grain cemented carbide strength and hardness, poor comprehensive performance is low, especially the high temperature strength of the alloy is not high, thermal shock and thermal plastic deformation ability is not strong, not suitable for working in high temperature environment, greatly limits the application of alloy.

In order to overcome the shortage of coarse grain cemented carbide production, recently, a new coarse grain cemented carbide preparation method has been put forward by scholars.

1.The 93.18wt% of coarse grain tungsten carbide powder WC, 6% cobalt powder, 0.12% radium powder, 0.2% rhenium powder, 0.1% vanadium carbide, 0.1% chromium carbide, 0.1% tantalum carbide, 0.1% titanium carbide, 0.1% nickel powder raw materials are fully mixed in alcohol medium; The mixture is then used in a ball mill for 25 hours of wet ball milling. After grinding, the wet mixture is transferred into a double cone mixer for alcohol recovery.

2.Drying; after cooling, pressing and forming, and adding 30% paraffin wax stereotyping agent in uninterrupted stirring for 3 hours.

3.The material was vacuum sintering, slowly sintering during the sintering process, and then maintain the temperature of 1400-1600 ℃ sintering temperature, holding time of 2 hours; holding time to maintain the temperature of 1400-1600 ℃, and then high-temperature high-pressure sintering, dwell time is 3 hours, sintered after cooling to obtain the present invention coarse grain cemented carbide.

Compared with the traditional method for preparing coarse-grained cemented carbide containing alkali metal ions Li, Na and K, the finished coarse grained cemented carbide product has the advantages of high thermal shock resistance and thermal plastic deformation resistance, and more high temperature, etc., more suitable for working in high temperature environment.

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