固溶处理对大厚度321不锈钢焊缝组织和性能的影响  

Effect of Solution Treatment on Microstructure and Properties of 321 Stainless Steel Weld

作　　者：段莉蕾 DUAN Lilei(Technology Center,CFHI Dalian Nuclear Power Petrochemical Co.,Ltd.,Dalian 116113,Liaoning,China)

机构地区：[1]一重集团大连核电石化有限公司技术中心,辽宁大连116113

出　　处：《焊管》2023年第11期14-19,共6页Welded Pipe and Tube

摘　　要：为了探究固溶处理后对大厚度321不锈钢焊缝的组织和性能,采用金相组织观察、铁素体测量、拉伸和冲击试验等手段,对200 mm大厚度321不锈钢TIG焊焊缝固溶处理后的微观组织变化、力学性能和耐腐蚀性能进行了研究。结果表明,固溶处理后原焊缝中的铁素体大部分溶解到基体中,铁素体含量由8%降低至小于0.5%,组织由柱状奥氏体+铁素体演变为柱状奥氏体和孪晶奥氏体混合组织。由于铁素体的溶解,使焊缝性能发生了改变,固溶处理后焊缝的室温、高温强度有所降低,特别是屈服强度降低幅度较大;材料的塑性和-196℃低温冲击韧性显著提高,强塑性综合指标更加接近母材锻件。固溶处理后的焊缝在敏化前、敏化后的腐蚀速率比值为1.03,敏化后晶间腐蚀比焊态焊缝更具免疫力。In order to explore the effect of solution treatment on the microstructure and properties of 321 stainless steel welds with large thickness,metallographic observation,ferrite measurement,tensile,and impact testing were used to study the microstructure changes,mechanical properties,and corrosion resistance of 321 stainless steel TIG welding welds with the thickness of 200 mm after solution treatment.The results showed that after solid solution treatment,most of the ferrite in the original weld seam was dissolved into the matrix,and the ferrite content decreased from 8%to less than 0.5%.The microstructure evolved from columnar austenite+ferrite to a mixed structure of columnar austenite and twin austenite.Due to the dissolution of ferrite,the weld performance has changed.The weld strength at room temperature and high temperature decreased after solid solution treatment,especially the yield strength decreased greatly.The plasticity of the material and the low⁃temperature impact toughness at-196℃have significantly improved,and the comprehensive strength plasticity index is closer to the base metal forging.After solid solution treatment,the corrosion rate ratio of pre⁃sensitization and post⁃sensitization weld after solution treatment was 1.03,which showed that sensitized intergranular corrosion is more immune than the original weld.

关 键 词：焊缝固溶处理 力学性能 腐蚀性能 焊缝组织 

分 类 号：TG142.71[一般工业技术—材料科学与工程]