A New Improvement Scheme for Spherical Tungsten Carbide Powder

The preparation methods of spherical tungsten powder are various. The domestic production method is mainly focused on the improvement of traditional production technology, so as to get the tungsten carbide powder with regular shape and fine structure. Recently, a kind of improved method of spherical tungsten powder has been put forward by some scholars.

1.To establish a stable operation of the argon plasma torch: the plasma reactor input 0.5MPa, 0.6MPa or 0.8MPa main working gas argon flow, auxiliary working gas hydrogen input pressure of 0.5MPa, 0.6MPa or 0.8MPa, the induction coil load to a certain power, the power can be 20 KW, 30 KW or 50 KW, at the same time, the igniter discharge, the induction coupling of the high voltage coil and the igniter corona trigger, the argon plasma is ionized to produce argon plasma torch. At this time, the whole plasma reactor is kept in the negative pressure state, which can ensure the stable operation of the plasma torch.

2.Nitrogen casting the cast tungsten carbide powder (original powder) into the argon plasma torch core high temperature zone heating. The cast tungsten carbide powder is sent to the high temperature area of the core of the plasma torch, absorbs a lot of heat, and the particle surface starts to melt. When the particle weight is 50% (or at least) melted, the tungsten carbide powder with high sphericity is formed due to the surface tension.

3.The tungsten carbide powder droplets were cooled and solidified to form spherical tungsten carbide powder. Under the action of four heating mechanisms, radiation, convection, conduction and chemistry, it is quickly heated and melted. When the particles melt to at least 50%, molten particles under the effect of surface tension of spherical droplet formation in a high degree, and in high temperature gradient (10 6K/m) under rapid cooling and heat exchange chamber to quench solidification, thus forming a spherical particle. This spheroidizing process can reach a nearly 100% spheroidization rate as long as the process parameters are properly set.

4.The gas is drawn off to collect spherical tungsten carbide powder. After the nodulizing process is completed, the gas is drawn off and discharged, and the nodularized powder enters the collecting tank and is automatically collected and collected.

In the whole spheroidizing method, it is essential to adjust and set the parameters of the argon plasma. The fine difference in the properties of the raw material powder, such as the particle size of the powder, will vary greatly in the process parameters. In general, this scheme has the advantages of low cost, stable quality and easy scale.

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