4Cr5MoSiV1钢的热变形行为及热加工图

Hot Deformation Behavior and Hot Processing Map of 4Cr5MoSiV1 Steel

摘要: 利用Gleeble-1500D热模拟试验机对4Cr5MoSiV1钢在950℃~1100℃，应变速率为0.01~10.0 s−1，最大应变量为50%的条件下进行了热压缩实验。结果表明：真应变–应力曲线在应变速率为10 s−1时出现波动现象；经计算得到4Cr5MoSiV1钢的激活能为416.16 kJ·mol−1，建立该合金的本构方程形式为，经验证与实验结果吻合较好；基于动态材料模型建立的热加工图可分为两个区域，在低应变速率0.01 s−1和0.1 s−1时为加工稳定区，且变形温度为1050℃时，能量耗散功率达到最大值0.3；在高应变速率1 s−1和10 s−1时为加工失稳区。结合变形组织的分析，合金在稳定区下具有较好的热加工性能。

Abstract: The hot deformation characteristics of 4Cr5MoSiV1 steel have been investigated by hot compression tests in the temperature range of 950˚C to 1100˚C at strain rates of 0.01 s−1 to 10.0 s−1 and maximum engineering strain of 50% by means of Gleeble-1500D thermal mechanical simulator. The results show that the true stress-strain curves exhibited oscillation behavior at strain rates of 10.0 s−1. The activation energy of 4Cr5MoSiV1 steel was calculated as 416.16 kJ·mol−1 and the constitutive equation was developed, namely on the basis of the testing data. The constitutive equation and testing results were nearly consistent by verification. The hot processing map developed base on dynamic materials model was divided into two domains. The stability domain appeared at lower strain rates (0.01 s−1 and 0.1 s−1), and at testing temperature 1050˚C, with a peak efficiency of power dissipation of 0.3. The instability domain appeared at higher strain rates (1 s−1 and 10 s−1). The optimum hot working condition was determined in the stability domain by combining with microstructure analysis.