固溶温度对316LN奥氏体不锈钢微观组织和高温力学性能的影响

Effect of solution temperature on microstructure and high temperature mechanical properties of 316LN austenitic stainless steel

对316LN奥氏体不锈钢进行了不同温度(1020、1050和1070℃)的固溶处理,利用电子万能试验机对316LN奥氏体不锈钢在300℃的高温环境下进行单轴拉伸试验,采用光学显微镜(OM)、透射电镜(TEM)和扫描电镜(SEM)对其微观组织和高温力学性能进行分析表征。结果表明:随着固溶温度的升高,316LN奥氏体不锈钢的晶粒尺寸逐渐增大,析出相逐渐溶解,位错密度降低的同时孪晶数量减少,抗拉强度和屈服强度略有降低,伸长率增加;高温下的拉伸断口形貌均呈现出典型的韧性断裂特征;当固溶温度为1050℃时,试验钢的晶粒尺寸均匀,析出相基本完全溶解,伸长率提高明显;在1050℃固溶保温120 min后,316LN奥氏体不锈钢的强塑性匹配较好。

316LN austenitic stainless steel was solution treated at different temperatures(1020℃,1050℃and 1070℃).The uniaxial tensile test of the 316LN austenitic stainless steel was carried out at 300℃by electronic universal testing machine,and microstructure and high temperature mechanical properties of the experimental steel were analyzed and characterized by means of optical microscope(OM),transmission electron microscopy(TEM)and scanning electron microscopy(SEM).The results show that with the increase of solution temperature,the grain size of the 316LN austenitic stainless steel increases gradually,the precipitates dissolve gradually,the dislocation density decreases,the number of twins decreases,the tensile strength and yield strength decrease slightly,and the elongation increases.The tensile fracture surface morphology at high temperature of the experimental steel shows typical ductile fracture characteristics.When the solid solution temperature is 1050℃,the grain size of the experimental steel is uniform,the precipitates are basically completely dissolved,and the elongation increases obviously.After solution treatment at 1050℃for 120 min,the strength and plasticity of the 316LN austenitic stainless steel match well.