消应力处理对316L焊接接头腐蚀性能的影响  

Effect of stress relief treatment on corrosion resistance of 316L welded joints

作　　者：张怀强 颜炳志 杨超平 刘成龙 张文洪 邹勇[2] ZHANG Huaiqiang;YAN Bingzhi;YANG Chaoping;LIU Chenglong;ZHANG Wenhong;ZOU Yong(Shandong Subang Construction Engineering Co.,Ltd.,Tengzhou 277500,Shandong,China;Shandong University,Jinan 250061,China)

机构地区：[1]山东速邦建设工程有限公司,山东滕州277500 [2]山东大学,济南250061

出　　处：《焊接》2025年第3期30-35,共6页Welding & Joining

基　　金：国家自然科学基金资助项目(51975331)。

摘　　要：【目的】该文研究了消应力处理对316L焊接接头耐蚀性的影响,为探明焊接残余应力对奥氏体不锈钢焊接接头耐蚀性的影响及改善耐蚀性提供科学依据。【方法】采用高频冲击技术对316L焊接接头进行消应力处理,测试了消应力前后近熔合线焊接热影响区残余应力的变化,并用电化学及慢应力应变拉伸法测试了焊接接头区域的耐蚀性。【结果】研究结果表明,焊接热影响区经过高频冲击消应力处理后,残余应力由拉应力转变为压应力;焊缝及热影响区的点蚀电位明显提高,钝化区间宽化及稳定,耐晶间腐蚀性能提高;焊接接头的应力腐蚀性能也得到了极大改善,应力腐蚀开裂时间增加了4倍。【结论】消应力前后晶间腐蚀和应力腐蚀性能都表现出很大的差别,有别于仅考虑贫铬区对耐蚀性的影响,残余应力对奥氏体不锈钢耐蚀性的影响是不可忽略的;一方面,残余应力通过增加钝化膜的缺陷来降低了点蚀性能;另一方面,残余拉应力可促进裂纹尖端的阳极溶解而降低了晶间腐蚀及应力腐蚀性能。高频冲击消应力处理产生的压应力降低了裂纹尖端的扩展开裂倾向,极大改善了奥氏体不锈钢的耐蚀性。[Objective]Effect of stress relief treatments on corrosion resistance of 316L welded joints was examined in this paper.It aimed to understand how welding residual stress affected corrosion resistance of austenitic stainless steel welded joints and enhance their corrosion resistance,thereby providing a scientific foundation for the improved performance.[Methods]High-frequency impact technology was employed for stress relief treatment on 316L welded joints,and changes of residual stress in welding heat affected zone near fusion line before and after stress relief were tested.Corrosion resistance of weld zone was evaluated by electrochemical methods and slow strain rate tensile tests.[Results]The results indicated that high-frequency impact stress relief treatment transformed residual stress in welded joints from tensile to compressive stress.This transformation significantly increased pitting potential of weld and heat affected zone,widened and stabilized passivation range,and improved intergranular corrosion resistance.Stress corrosion resistance of welded joints was greatly improved,and stress corrosion cracking time increased by 4 times.[Conclusion]There was a significant difference in intergranular corrosion and stress corrosion resistance before and after stress relief.Unlike solely considering influence of chromium-depleted zones on corrosion resistance,effect of residual stress on corrosion resistance of austenitic stainless steel must not be overlooked.On one hand,residual stress impaired pitting corrosion resistance by increasing defects in passivation film.On the other hand,residual tensile stress could promote anodic dissolution at crack tips,thereby reducing intergranular corrosion and stress corrosion resistance.The compressive stress induced by high-frequency impact stress relief treatment reduced crack propagation tendency at the crack tip,significantly improving corrosion resistance of austenitic stainless steel.

关 键 词：奥氏体不锈钢 消应力处理 晶间腐蚀 应力腐蚀 

分 类 号：TG406[金属学及工艺—焊接]