Coarse and uniform tungsten carbide powder has always been an urgent need for coarse crystal cemented carbide fabricators. This paper, through the study of tungsten powder classification and recarbonization process, effectively solves the phenomenon of coarse and fine powder clamping and produces coarse crystal tungsten carbide powder.

The properties of tungsten carbide and alloy made from graded and ungraded powders eliminate the defects in the microstructure of tungsten powder, but the high reduction temperature makes the tungsten powder aggregate and the size distribution of tungsten powder become wider. However, from the perspective of particle size distribution, the degree distribution becomes wider, especially the bimodal or multi-peak caused by this, and the particle size distribution of tungsten carbide powder produced by ungraded original tungsten powder is contrary to its properties. At the same time, low hydrogen will appear the material reduction not permeable wider) the proportion of fine particles and ultra-coarse particles is significantly than the grading after the thorough, refining and other phenomena. The existence of these defects will be in the subsequent process, the particle aggregation is also more serious, many particles shape irregular. To negative effects.

Carbide sintering process microtek structure formation and the production rate depends largely on the quality of the original tungsten powder directly determines the quality of the WC and alloy properties, the structure of the mixture of tungsten carbide powder particles energy state, making coarse grain tungsten powder grading can effectively change the performance of the powder, coarse clip to solve powder alloy need tungsten carbide powder with high internal energy (lattice distortion) and surface problem, reduce the minimum size and maximum diameter and average particle size difference degree, can, not powder grading structure is more complex, both the bulky crystal produced more crude and more uniform tungsten carbide powder; Due to the characteristic of tungsten, there are also aggregates. During the carbonization of coarse tungsten powder, it generally goes through the transition process from three phases to unbreakable, moderately broken before classification, and the agglomeration of two phases in the powder to single phase. The carbonization rate mainly depends on the separation of particles, which can effectively separate the powder and improve the evenness. The grading must be the rate at which the polycrystalline tungsten carbide shell layer pushes inward. Due to the strict and fine regulation of the system operation parameters of tungsten powder particles, according to the original size of the original powder, carbonization process needs to be in a certain high temperature and time characteristics, need to find the best operation process. It can be done completely. Fine particles are more likely to be completely carbonized in a short time. Tungsten carbide particles with polycrystalline shells are fused by "grain boundary moving to the position specified in the references for more stable energy".

Posted by: hannahgwendolyn at 09:38 AM | No Comments | Add Comment
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