Spherical Cast Tungsten Carbide Powder Preparation Technology for Hard Surface Material

The surface morphology, microstructure and particle size of cast tungsten carbide have a decisive influence on its application effect. Spheroidizing and rapid cooling of traditional cast tungsten carbide powder can significantly improve the toughness of hard surface materials containing cast tungsten carbide, and achieve the best combination of high wear resistance and high toughness of hard surface materials.

In recent years, Zigong cemented carbide in China has been produced by direct melt atomization, and the method of producing spherical cast tungsten carbide powder by atomization has also been developed. However, without exception, the above spherical cast tungsten carbide preparation method has some problems, such as large gas consumption, poor control stability of sphericity of powder due to the strong impact of air flow during the spherical forming process.

Researchers in China have continuously improved the technology and developed a preparation method of spherical cast tungsten carbide powder with high yield, low energy consumption and no material need to be recycled. Its technical case is optimized as follows:

The original tungsten carbide powder was used as raw material. The bulk density of the powder was 7.02g/cm³, the fluidity was 10.74s/50g, the total carbon was 3.94%, and the free carbon was 0.076%. The total heating power of spheroidizing furnace is 160 kw, the material loading channel is 5, the soaking zone length of the material loading channel is 1.8 m, the diameter of the material loading channel is 70 mm, the feeding capacity of the single material loading channel is 18 kg/h, the spheroidizing temperature is 3000 (+50 ℃), the flow rate of N₂ in the spheroidizing furnace is 60 L/min, and the speed of the cooling plate is 1000rpm. The yield of spheroidized powder is 98.5%, particle size is 80+120 mesh, spherical cast tungsten carbide powder is nearly 98%, loose density is 10.04g/cm3, fluidity is 5.5s/50g, total carbon is 3.99%, free carbon is 0.066%, microhardness HV0.05 is 980kgf/mm², acicular eutectic structure is more than 90%.

Different from the previous process, the improved technology is the best way to prepare spherical cast tungsten carbide powder with one-time pelletizing, no material need to be recycled, powder yield > 95%, high yield and low energy consumption.

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