超高强度钢热流变行为

Research on hot forming behavior of ultrahigh strength steel

热冲压成形工艺是将冲压成形工艺和淬火工艺集成在同一工序中进行的新型成形工艺。根据热冲压工艺的时间-温度特征,采用Gleeble3800热模拟系统,在温度600℃~800℃和应变速率0.01/s^0.5/s下,对热冲压钢板USIBOR1500进行热拉伸实验,获得了相应的应力-应变曲线,并利用最小二乘法进行多元线性回归,建立USI-BOR1500钢板的热变形抗力数学模型。结果表明,USIBOR1500钢的热变形行为符合应变硬化加动态回复机制,变形温度和应变速率对其力学性能有很大的影响,变形温度的影响更为强烈。在热变形情况下,USIBOR1500钢板的抗拉强度大幅下降。建立的数学模型与实验数据吻合较好。

Hot stamping process is a new kind of process combine forming and quenching in the same process. According to the characteristic of time-temperature of hot stamping, tensile experiments were carried out on hot stamping steel USIBOR1500 in a range of temperature 600℃ -800℃ and strain rate 0. 01/s-0. 5/s with the test machine Gleeble3800, and the corresponding stress-strain curves were obtained. The mathematic model of deformation resistance of steel is based on liner regression with least-square method. Results show that, the hot forming behavior of USIBOR1500 accord with the hardening and followed by dynamic recovery, the forming temperature and the strain rate have great effect on the hot forming behavior of USIBOR1500 and the effect of forming temperature is more intensive. Hot forming can reduce the tensile strength greatly. The mathematic model of deformation resistance of steel agrees well with the experimental data.