High-strength of Ultrafine-grained Cemented Carbide by Optimizing the Molding Process

The relationship between molding and strength in ultrafine-grained cemented carbides remains unclear, as few studies have focused on optimizing the molding process. Therefore, we produced cemented carbides by varying the WC raw material particle size and molding aid. It was found that the smaller the WC raw material particle size, the lower the relative density after molding. Furthermore, the bending strength of green compact does not correlate with the bending strength of normal sintering, but the relative density of green compact correlates with bending strength of normal sintering. In other words, to achieve high bending strength of normal sintering, it is effective to improve the relative density of green compact while maintaining a minimum level of bending strength of green compact. It was found that the optimal approach is the combined addition of stearic acid to improve the relative density of green compact and paraffin wax to enhance bending strength of green compact. The optimized molding aid was applied to the ultrafine-grained cemented carbide, which improved its bending strength. This highlights the importance of molding process optimization for high-strength cemented carbides.