模具温度对汽车B柱变强度热成形零件过渡区的影响

Influence of die temperature on transition zone of hot stamping parts with variable strength for automotive B-pillar

以某汽车B柱为研究对象,设计了"上模-上压料板-压边圈-下模"的复合型变强度热成形工艺方案,利用Autoform软件的热成形模块对该汽车B柱零件变强度热成形工艺进行了分析和优化。以该数值模拟方案为基础,以零件软硬区分界线两侧的马氏体含量为参考,研究了冷热区模具温度对零件过渡区的位置、宽度的影响规律:在变强度热成形过程中,由于零件软区的温度更容易因为热量的散失而降低,使得热区模具的温度成为影响零件过渡区位置和宽度的主要因素;随着热区模具温度降低,零件过渡区位置向软区方向偏移,过渡区宽度增加;550℃时,零件过渡区偏移量最小,约为0. 5~1 mm,过渡区宽度最小,约为17. 8~18. 3 mm。

For the automobile B-pillar,the hot stamping process scheme with variable strength of upper die-upper press plate-blank holder-lower die was designed,and the hot stamping process of automobile B-pillar with variable strength was analyzed and optimized by the hot stamping module of software Autoform. Based on the numerical simulation scheme,the influences of die temperature in the cold and hot sections on the transition zone position and width of part were investigated by taking the martensite content on the both sides of boundary between hard and soft areas as reference. During the hot stamping process with variable strength,the die temperature in the hot section becomes the main factor influencing the transition zone position and width of part due to the temperature in the soft area of part decreasing with the heat loss easily. With the decreasing of die temperature in the hot section,the position of transition zone shiftes to the soft zone of part,and the width of transition zone increases. When the die temperature in the hot section is 550 ℃,the shifting amount and the width of transition zone are up to minimum about 0. 5-1 mm and 17. 8-18. 3 mm,respectively.