固溶温度对06Cr25Ni2奥氏体耐热钢微观组织和力学性能的影响

Effect of Solution Temperature on Microstructure and Mechanical Properties of 06Cr25Ni20 Austenitic Heat-resistant Steel

以热轧态06Cr25Ni20奥氏体耐热不锈钢为研究对象,采用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM),结合硬度检测和拉伸试验等手段,研究了固溶温度对该材料微观组织和力学性能的影响。结果表明,热轧态耐热奥氏体不锈钢加工硬化严重、塑韧性差;固溶处理后其强度和硬度均下降,塑韧性则明显提高;随着固溶温度的升高,晶粒的方向性消除,晶粒尺寸变小且显微组织更为均匀,晶界上分布的Cr23C6相逐渐减少且消失;热轧态和1 000℃固溶处理后的室温拉伸断口呈脆性断裂特征,而经1 050℃以上固溶处理后,室温拉伸试样断口呈韧性断裂特征。

The hot-rolled 06Cr25Ni20 austenitic heat-resistant stainless steel was taken for subject of the research. The effect of solution temperature on microstructure and mechanical properties was investigated by optical microscope(OM),scanning electron microscope(SEM),transmission electron microscopy(TEM),hardness measurements and tensile tests. The results showed that the hot-rolled austenitic heat-resistant stainless steels had serious work-hardening and poor plasticity,and strength and hardness decreased but plasticity improved greatly after solution treatment. With the increase of solution temperature,grains distributing along the rolling direction disappeared and the microstructure gradually became smaller and more uniform,and Cr23C6 phases distributing along the grain boundaries decreased and eventually disappeared. The room-temperature tensile fractures of samples hot-rolled and solution treated at 1 000 ℃ presented brittle fracture feature,while those solution treated at above 1 050 ℃ presented plastic fracture feature.