超高强度钢的热冲压成形极限

Hot stamping forming limit of ultra high strength steel

超高强度钢板作为轻量化材料广泛应用于热冲压中,研究其高温下的力学性能显得尤为重要。首先对超高强钢B1500HS进行了胀形实验,研究了常温,700℃,800℃下的成形极限曲线(FLD);同时,运用有限元软件建立了FLD非线性和线性数值计算模型,对高温成形极限曲线进行了数值模拟预测。研究发现,常温下可以通过改变润滑条件拓展双拉区域数据点,而高温下双拉区域数据点较少,且缺少等拉数据点;数值模拟可以对热冲压FLD进行准确的预测,非线性计算模型比线性计算模型稳定,且更加接近实验曲线,数值模拟曲线范围更广,且仿真时通过改变摩擦系数可以获得高温下等拉数据点。

The ultra high strength steel as a kind of lightweight material is widely used in hot stamping,and it is important to research its mechanical properties at high temperature. First,the bulging experiment was conducted to study the forming limit curves（ FLD） of ultrahigh strength steel B1500 HS at room temperature,700 ℃,800 ℃ respectively. At the same time,the nonlinear and linear calculating models were built to predict the FLDs at various temperatures. The results show that the dual pull area data points are expanded by changing lubrication conditions at room temperature,while at high temperature the data points in dual pull area are less and lacking equivalent pull data points. The nonlinear calculating model is more stable and accurate than linear calculating model,and the equivalent pull area points are obtained by changing the friction factor at high temperature in simulation.