针对采用SKD61钢制造的某型号汽车塑件注塑模具的关键零件—型腔在生产过程中出现的开裂失效现象,通过宏观和微观形貌分析、化学组分分析、显微组织分析、硬度测试等方法,分析型腔开裂的原因。结果表明,SKD61钢的热处理不当、零件在工作中表面与心部产生过高的温度梯度等是导致零件发生开裂失效的主要原因。 Aiming at the key part of plastic injection mold for a certain type of automobile made of SKD61 steel, the cracking failure phenomenon appeared in the process of cavity, through macro and micro-morphology analysis, chemical composition analysis, microstructure analysis, hardness test, etc. Method to analyze the cause of cavity cracking. The results show that SKD61 steel heat treatment improper, parts in the work of the surface and the heart of the temperature gradient is too high cause the parts of the main cause of cracking failure.