针对硬质合金挤压棒坯溶剂脱脂过程中发生开裂的原因进行了分析,重点讨论了成型剂偏析、脱脂温度、液固质量比、残余内应力等因素的影响.结果表明:成型剂的偏析极易使棒坯在溶剂脱脂过程中由于蜡的脱除形成裂纹源;而棒坯从挤压模挤出后,在较短时间内快速冷却,成型剂中的大分子链来不及进行构象调整便被冻结,造成了棒坯的残余内应力,在溶剂脱脂过程中内应力释放导致裂纹源扩展使棒坯开裂;可以用退火的方法降低挤出棒坯的残余内应力,避免脱脂开裂.

Factors leading to the cracking of cemented carbide extruded bar during solvent debinding process were studied.Effects of binder accumulation,debinding temperature,liquid/solid mass ratio and residual stress were considered.The results showed that the cracking origin was apt to be formed during the solvent debinding process because of the binder accumulation.While the residual stress,which was generated because the polymer chain couldnt adjust the conformation during the quickly cooling of extruded green parts,was the most significant element.The release of residual stress enlarged the cracking origin and led to the cracking.An annealing process of the green parts can be done to solve the problem.