Why does the hardness of cemented carbide depend on the cobalt content?

Because cobalt is a soft fat, it plays a bonding role in tungsten-cobalt cemented carbide. Therefore, the less the cobalt content, the higher the proportion of hard phase and the higher the hardness; for the same cobalt content, the finer the carbide grains, the higher the hardness.

In order to further improve the quality and production stability of ultrafine cemented carbide with low cobalt content (mass fraction), the influence of wet grinding time in the production process parameters of ultrafine cemented carbide mixture on the microstructure, hardness and bending strength of ultrafine alloy was preliminarily discussed. The results show that for the production of low-cobalt ultrafine cemented carbide, long-term wet grinding of the mixture mainly plays a role in mixing and activation, and has a small effect on the crushing of the mixture powder. However, if the wet grinding time is too short (<60h), it is easy to form micropores and cobalt pools in the alloy, while if the wet grinding time is too long (>90h), it is easy to form grain growth and The coarse inclusion phenomenon will eventually affect the hardness and bending strength of low-cobalt ultrafine cemented carbide.

As a new type of mining tool material, the wear resistance and failure behavior of coarse-grained WC-Co cemented carbide under different working conditions have an important impact on its industrial application. The effect of cobalt content on the impact abrasive wear performance of coarse-grained cemented carbide with a WC grain size of 5μm. When the mass fraction of cobalt increases in the range of 6% to 14%, the wear coefficient K of cemented carbide increases linearly, and the impact abrasive wear resistance decreases linearly. The impact abrasive wear mechanism of coarse-grained cemented carbide is: the cobalt bonding phase of the surface layer is first worn by Si C particles, and then the wear resistance of the alloy mainly depends on the failure behavior of the protruding WC particles. Therefore, the wear coefficient K of cemented carbide is proportional to the volume content of WC hard phase.