双金属复合板光纤激光焊接及其接头腐蚀性能分析  

Fiber Laser Welding of Bimetallic Plates and Corrosion Property of the Joints

作　　者：苟宁年[1] 张建勋[1] 李振岗[1] 

机构地区：[1]西安交通大学金属强度国家重点实验室,陕西西安710049

出　　处：《稀有金属材料与工程》2016年第7期1760-1764,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金项目(51375370);国家高技术研究发展计划("863")计划(2013AA031303HZ)

摘　　要：针对DSS2205/X65双金属复合板进行激光对接焊试验,观察焊接接头的金相组织,通过能谱法分析Cr元素在焊接接头中的分布,测试了母材DSS2205和焊接接头的极化曲线。结果表明：焊接接头中金相组织沿厚度方向上出现了明显的分层特征;激光焊接时熔池中上下2个部位的熔态金属流动符合Marangoni对流特征,熔池中部的液态金属更趋向于向上流动扩散,而受重力影响较少;焊接接头复层的极化曲线表明它们和母材DSS2205具有相当的自腐蚀电位,但点蚀电位均低于母材DSS2205,并且采用小光斑激光焊接具有更好的抗点蚀能力。双金属复合板是将基层（10-60 mm的碳钢或低合金钢）与复层（1-5 mm的不锈钢或钛合金等）在一定的高温高压下冶金地结合在一起,使其成为一种具有特殊性能的整体新型材料,已广泛用于石油化工、海洋开发、造船等工业领域。使用双金属复合板的主要目的在于充分利用其基层材料的高强度、高塑韧性和复层的耐热、耐磨、耐腐蚀等性能,然而,在结构制造中,由于2种不同的材料属性给其焊接带来了新的问题。例如,焊接接头过渡层，The DSS2205/X65 bimerallic plates were welded by fiber laser,and the microstructure of the welded joint was observed by OM.The distribution of the Cr element in the welded joint was studied to infer the fluidity of molten pool.The potentiodynamic scanning method was employed to measure the anodic polarization curves of DSS2205 base metal and the welded joint.The results show that the microstructure of the welded joint exhibits a hierarchical characteristic along thickness direction of the welded joint.The Cr distribution in the welded joint indicates that the fluidity of molten pool possess the characteristics of Marangoni convection,the molten metal in molten pool tends to spread upward flow,and is less affected by gravity.Polarization curves reveal that the corrosion potential between the composite layer of the joint and the DSS2205 base metal is similar,but the pitting potential of the welded joint is lower than that of the base metal DSS2205.The joint welded by laser beam with a small focusing spot size shows a better point corrosion resistant ability compared with the joint welded by laser beam with a big focusing spot size.

关 键 词：双金属复合板 激光焊 熔池流动 极化曲线 

分 类 号：TG456.7[金属学及工艺—焊接]