凹模温度对AZ31B镁合金板材冲压成形性能的影响

Formability of AZ31B Magnesium Alloy Sheet Under Different Die Temperatures

采用Nakazima半球凸模胀形法获取不同凹模温度下AZ31B镁合金板材的成形极限曲线(FLC),研究了温冲压过程中凹模温度对镁合金板材成形性能的影响.运用有限元法对等双拉试样进行热-力耦合模拟,得到不同凹模温度下的温度场,分析AZ31B镁合金板材与凹模在热传递过程中的热-力耦合关系.另外,通过试制汽车行李箱铰链支架盖板零件,验证了实际工况下凹模温度对AZ31B镁合金板材成形极限的影响.结果表明:凹模温度的降低,会显著改变AZ31B镁合金薄板成形时的温度梯度分布,造成材料成形极限的下降以及破裂位置的改变;不同凹模温度下所得FLC的模拟值与其实验值相符.

To investigate the effect of die temperature on formability of AZ31 B magnesium alloy sheet in stamping,forming limit curve(FLC)of AZ31 B magnesium alloy sheet was obtained through Nakazima semispherical drawing under different die temperatures.Thermo-mechanical coupling effect under heat transfer between AZ31 Bmagnesium alloy sheet and die was analyzed based on temperature fields of biaxial tension specimens obtained by thermo-mechanical coupled simulation using finite element method.Effect of die temperature on forming limit of AZ31 Balloy sheet in working condition was finally verified in a tryout stamping of hinge cover.The results show that temperature gradient distribution of AZ31 B magnesium alloy is highly changed with the decline of die temperature,forming limit is thus decreased and fracture position is also affected.The FLCs under different die temperatures are proved to be in good agreement with actual stamping of AZ31 Balloy sheet.