Tungsten Carbide Button — Tungsten Powder Reduction (2/2)

Except reduction temperature, the thickness of the material layer will affect tungsten powder granularity and distribution. Theoretically, increasing thickness of the material reduction of tungsten powder tungsten powder particles loaded boat will thicken; and in turn reduce the material thickness of tungsten powder particle size means the boat will be relatively finer. However, in actual production, thick boat loading volume will cause the powder particle size distribution is widened, especially caused bimodal, multimodal and tail peak. In addition, WC powder of different particle size distribution produced by the hardness of tungsten carbide button as the particle size distribution will be broadened and significantly reduced. The reason is that the particle size distribution wider tungsten powder there will be large differences in the thickness of the particles, the difference in the process of carbonation will cause uneven WC grain growth, which make the same batch of powder in both the coarse particles have a single crystal by the fine-grained particles composed of polycrystalline. When the carbonization temperature is low, the fine particles carbonization completely, while the coarse particles are non-complete; when the high temperature carbonization, coarse grains are also complete carbonized, but the fine particles becomes single crystal and grows up.

In the production of tungsten carbide buttons, use single crystal and polycrystalline particles coexisted WC powder, mixed alloy material crushing prolonged, single crystal grains not crushed easily or crushed consistency is poor. Thus, by optimizing the production process of tungsten powder, such as reduction temperature control, carbonization temperature, the amount of loading the boat, etc., to fabricate homogeneous single crystal or polycrystalline WC powder, which is beneficial for improving the performance of tungsten carbide buttons.

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