2507超级双相不锈钢的流变应力本构关系及热加工图

采用Gleeble-3800热模拟试验机研究了热变形温度为950~1200 ℃、应变速率为 0.01~10 s^-1条件下2507超级双相不锈钢的热压缩变形行为,并借助光学显微镜观察了不同变形过程中的微观组织演化。基于试验数据分析,建立2507超级双相不锈钢的流变应力本构关系及热加工图。结果表明:流变应力随着变形温度的升高和应变速率的降低而逐渐降低,在高应变速率下,流变曲线出现“类屈服平台”。试验钢的热变形激活能为414.57 kJ·mol^-1,应力指数为4.18,峰值应力本构方程为ε·=3.69×10¹⁵sinh(0.0101σ)]^4.18exp-414.57RT,根据微观组织分析及热加工图确定出试验钢的最佳热加工区域为热压缩温度1060~1120 ℃,应变速率0.01~0.1 s^-1。

Flow stress constitutive relationship and processing map of super duplex stainless steel 2507

Hot deformation behavior of super duplex stainless steel 2507 was investigated by using Gleeble-3800 thermal simulation testing machine under the conditions of hot deformation temperature of 950-1200 ℃ and strain rate of 0.01-10 s^-1. And the microstructure evolution in different deformation processes was observed with the help of optical microscope. Based on the experimental data analysis, the flow stress constitutive relationship and processing maps of the super duplex stainless steel 2507 were established. The results show that the flow stress gradually decreases with the increase of deformation temperature and the decrease of strain rate, and the rheological curves appear as “yield-like platform” at a high strain rate. The activation energy of hot deformation and the stress index of the steel are 414.57 kJ·mol^-1 and 5.18, respectively. The peak stress constitutive equation is ε·=3.69×10¹⁵sinh(0.0101σ)]^4.18exp-414.57RT. According to the microstructure analysis and processing maps, the optimized process range of the steel is the deformation temperature of 1060-1120 ℃ and the strain rate of 0.01-0.1 s^-1.