固溶处理对309S不锈钢组织和力学性能的影响

Effect of Solution Treatment on Microstructure and Mechanical Properties of 309S Stainless Steel

通过拉伸试验和显微硬度测试,光学显微镜和扫描电镜观察,研究了固溶处理对309S奥氏体不锈钢组织和力学性能的影响。结果表明,在固溶处理后,铁素体含量由11.6%降低到7.3%;随固溶温度升高和时间延长,碳化物逐渐溶解,奥氏体晶粒逐渐长大;强度和显微硬度随着保温时间的增加逐渐降低;309S不锈钢经1 100℃×20min保温+固溶处理,水冷后其屈服强度、抗拉强度分别达到259.71 MPa和575.31 MPa,伸长率为58.4%,显微硬度(HV_(0.2))为178.7;拉伸试样断口呈现出以韧窝为主的断口形貌,塑性高于热轧板。

The effects of solution treatment on the mechanical properties and microstructure of 309S stainless steel plate were investigated by OM （optical microscopy）, SEM（scanning electron microsco- py）, room temperature tensile and micro-hardness test. The results show that the volume fraction of ferrite phase in the 309S steel is obviously reduced from 11.6% to 7.3% after solution treatment. The increase of solution temperature and time can be beneficial for both the dissolution of carbide and austen- ite grain growth. In addition, strength and micro-hardness of the 309S stainless steel are decreased with increasing in hold time. With solution at 1 100 ℃ for 20 min and then water cooling, the yield strength, ultimate tensile strength, micro-hardness and elongation of the 309S stainless steel reach 259.71 MPa. 575.31 MPa. 178.7 HV_0.2 and 58.4%, respectively. The fracture of the specimen is characterized by ductile dimple,and toughness of the specimen after solution treatment is better than that of the hotrolled sheet.