汽车零部件热成形极限裕度云图的构建与应用

Establishment and Applications of Thermal Forming Limit Margin Field Graph for Automobile Components

在热冲压工艺中,热冲压钢板处于高温状态,不同位置温度分布有明显差异,传统方法难以评价冲压件的成形性,考虑温度的三维成形极限图能有效评价热冲压件的成形性能,但无法判断热冲压件的安全裕度。针对上述问题,在考虑温度的三维成形极限图的基础上,首先提出了成形裕度的计算方法;然后结合数值模拟和理论分析手段,构建了适用于评价高强钢板热冲压的安全裕度云图;最后对某汽车B柱热冲压不同工艺过程进行了仿真分析,并与试验进行了对比。结果表明,在不同工艺参数和板料尺寸下,构建的裕度云图均能有效预测高强钢板热冲压件的开裂部位和程度。

In hot stamping processes,the sheet maintained in a high temperature state and the temperature varied at different positions,for which traditional method was difficult to evaluate the sheet formability.Temperature dependent 3D forming limit graph was a new method to evaluate formability of hot stamping components,however,the prediction of forming margin remained a blank.To solve the problems discussed above,a way to calculate the forming margin was proposed herein based on the temperature dependent 3D forming limit graph.Then,combining numerical simulations and theoretical analyses,a safe margin field graph for evaluating high strength steel sheet in hot stamping was established.Using the safe margin field graph,different hot stamping processes of an automobile B pillar were analyzed by numerical simulation and were compared to experiments.Results show that the proposed forming margin field graph may effectively predict the fracture positions and cracked degrees of HSS components in hot stamping at different process parameters and blank shapes.