乘用车尾板用HC180BD+Z钢冲压开裂原因分析

Analysis of Stamping Cracking Causes of HC180BD+Z Steel for Passenger Car Tailboard

利用光镜、拉伸方法对HC180BD+Z开裂零件的显微组织、力学性能和烘烤硬化效果进行了分析,并通过对热轧、冷轧和连镀工艺等多工序进行对比分析以找出钢种开裂原因。结果表明:冲压过程中产生开裂现象与退火工艺有关,即带钢在退火过程中前段加热温度过高且退火速度较低会造成冷轧变形组织畸变能和位错密度的降低,导致在后续高温退火中形核率降低,从而出现局部混晶组织,在冲压过程中产生开裂缺陷。

Experiments were conducted on the microstructure,mechanical properties,and baking hardening effect of HC180BD+Z cracked parts using optical microscopy and stretching methods.Multiple processes such as hot rolling,cold rolling,and continuous plating were compared and analyzed.The results indicate that the cracking phenomenon during the stamping process is related to the annealing process,that is,the high heating temperature and low annealing speed in the early stage of the annealing process of the strip steel will cause a decrease in the distortion energy and dislocation density of the cold rolled deformation structure.In the subsequent high-temperature annealing,the nucleation rate will decrease,leading to the occurrence of local mixed crystal structure and cracking defects during the stamping process.