稀土Ce对18Cr-5Ni-4Cu-N奥氏体不锈钢热压缩性能的影响

Effect of rare earth Ce on hot compression of 18Cr-5Ni-4Cu-N austenitic stainless steel

采用Gleeble-1500D热模拟机对加入质量分数0.006 3%Ce的18Cr-5Ni-4Cu-N奥氏体不锈钢进行热压缩测试,测定变形温度为1 273~1 473 K和应变速率为0.01~10 s^(-1)时热变形的应力-应变曲线,采用Zener-Hollomon参数法构建高温本构方程,计算能量耗散图,并且采用场发射扫描电镜对高温变形组织进行研究。结果表明:加入质量分数0.006 3%Ce的18Cr-5Ni-4Cu-N奥氏体不锈钢热变形激活能为437.85 kJ/mol,与未加稀土试验钢的变形激活能数值相比没有明显差异;能量耗损图表明加入质量分数0.006 3%Ce的试验钢热加工最优区域范围为1 370~1 473 K的温度范围内应变速率大于1 s^(-1),峰值效率大于0.2的区域;钢中的稀土复合夹杂随基体产生塑性变形改善了试验钢的加工性能。

The hot compression test of 18 Cr-5 Ni-4 Cu-N austenitic stainless steels with 0.006 3% Ce added was carried out by using Gleeble-1500 D thermal simulator. The stress-strain curve of hot deformation was tested when the deformation temperature was 1 273-1 473 K and the strain rate was 0.01-10 s^(-1). The constitutive equation of high temperature plastic deformation was constructed by Zener-Hollomon parameter method, and the power dissipation map was calculated. Meanwhile, the high temperature deformed structure was studied using the field emission scanning electron microscope. The results showed that the activation energy of 18 Cr-5 Ni-4 Cu-N austenitic stainless steel with 0.006 3% Ce added was 437.85 kJ/mol. There was no significant difference compared with the deformation activation energy value of the tested steel without rare earth added. The power dissipation map showed that the optimal area for thermal processing of the tested steel with 0.006 3% Ce added was the area where the strain rate was greater than 1 s^(-1) and the peak efficiency was greater than 0.2 in the temperature range of 1 370-1 473 K. The rare earth composite inclusions in the steel produce plastic deformation along with the matrix, which improved the processing performance of the tested steel.