06Ni31Cr19Mo2Nb含铌奥氏体不锈钢热变形行为及其热加工图

Hot deformation behavior and hot processing map of 06Ni31Cr19Mo2Nb austenitic stainless steel containing Nb

采用Gleeble-3500热模拟试验机对06Ni31Cr19Mo2Nb含铌奥氏体不锈钢进行高温单道次热压缩试验,研究了其在不同变形温度（950～1100℃）和应变速率（0. 01～1 s-1）条件下的热变形行为及组织变化规律,并且根据试验条件下真应力-真应变曲线,推导了该材料的热变形方程和热加工图。研究结果表明：流变峰值应力随温度升高或应变速率降低而降低;变形温度越高,应变速率越低,试验钢发生动态再结晶行为愈发显著。计算出该试验钢的热变形激活能为365. 111 k J·mol-1。基于动态材料模型绘制出不同应变量下的热加工图,其失稳区域和最优热加工区域的分布具有相似性。变形温度在990～1070℃,应变速率0. 0316～0. 1 s-1范围内,材料热加工性能最佳,能量耗散率为43%～45%。

The one pass thermal compression test at high temperature of 06Ni31Cr19Mo2Nb austenitic stainless steel containing Nb was carried out by using Gleeble-3500 thermal simulation machine. The hot deformation behavior and microstructure evolution of this alloy at different temperatures（ 950-1100 ℃） and different strain rates（ 0. 01-1 s^（-1）） were investigated,the hot deformation equation and hot processing map of the material were derived according to true strain-true stress curves under experiment conditions. The results show that the flow peak stress decreases with the increase of temperature and the decrease of strain rate. The higher the deformation temperature and the lower the strain rate are,the more obvious the dynamic recrystallization behavior of the test steel occurs. The calculated activation energy for deformation of the test steel is 365. 111 kJ·mol^（-1）. According to the dynamic material model,the hot processing map under different strains is drawn,and the distribution of the instability regions is similar to the distribution of optimal hot processing regions. The energy dissipation efficiency is 43%-45% when strain rate is 0. 0316-0. 1 s^（-1）,temperature is 990-1070 ℃,and processing performance of the material is the best.