异种不锈钢激光焊接相结构变化对腐蚀特性的影响  

Effects of microstructure change on corrosion resistance of dissimilar stainless steel joint by laser welding

作　　者：姚星[1,2] 段红平[1] 李光[1] 夏原[1] 

机构地区：[1]中国科学院力学研究所,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《材料热处理学报》2013年第2期72-76,共5页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金重点项目(10832011)

摘　　要：为了研究异种材料焊缝的耐腐蚀性能,对316L与304不锈钢进行了激光焊接。通过组织观察和XRD技术检测了母材及焊缝微区的组织结构,采用动电位极化的方法测试了316L和304奥氏体不锈钢及其激光对接焊缝的耐腐蚀性能,并分析了焊缝耐腐蚀性提高的原因。结果表明,在室温3.5%NaCl溶液中,焊缝及母材的腐蚀均以点腐蚀为主,且点蚀基本在晶界处萌生,焊缝的耐腐蚀性相对母材有了明显的提高;激光焊缝组织的晶粒尺寸较母材明显细化,相成分以奥氏体为主,有明显的择优生长取向,且奥氏体含量相对母材有所增加,这种相结构特征的变化是焊缝耐腐蚀性提高的主要原因。In order to study the corrosion resistance of dissimilar material weld, butt weld joint of 316L and 304 austenitic stainless steel was prepared by laser welding. The microstructure and phases of the weld joint were investigated by optical microscope and X-ray diffraction. The electrochemical corrosion behavior of the dissimilar metal weld joint and two base materials was studied by potentio dynamic polarization test in 3.5% NaC1 solution at room temperature. Results show that pitting mainly at grain boundary and the weld exhibits better corrosion resistance in 3.5% NaC1 solution compared with base metals. At the same time, the weld has more refined grains, the amount of austenite is increased and the preferential growth of austenite is obvious in weld, which is the main reason for enhancing electrochemical corrosion resistance.

关 键 词：奥氏体不锈钢 激光焊接 异种焊缝 电化学腐蚀 

分 类 号：TG142.7[一般工业技术—材料科学与工程]