旁路分流电弧熔钎焊铝/镀锌钢板接头腐蚀研究

Research on corrosion of aluminum/galvanized steel joint by bypass-current arc welding-brazing

为了探究铝/钢熔钎焊复合接头性能及其腐蚀行为,采用旁路分流电弧熔钎焊接6061铝合金与镀锌钢板,结果表明,焊缝成形均匀美观,接头呈现熔钎焊接头形貌。腐蚀形貌图中,焊缝区域腐蚀面积高于母材区域,而腐蚀极化曲线和后半段阻抗谱表明腐蚀后期钢母材耐腐蚀性最差,腐蚀最快,焊缝界面层次之,铝母材耐腐蚀性最优,腐蚀最慢。利用旁路电弧与MIG主弧形成耦合电弧产生分流作用,改变作用于熔滴和熔池的力场分布和热输入,在保证焊接成形的同时避免焊接缺陷的产生。在腐蚀测定中,不同区域单位面积发生腐蚀反应数量及元素分布不同是引起腐蚀速率变化及腐蚀程度存在差异的主要因素。分析不同组织区域对接头腐蚀性能的影响,为工程应用中提高熔钎焊接接头质量提供了理论数据支持。

In this study,we examined the performance and corrosion of aluminum/galvanized steel welding-brazing joints. After using the by-pass current arc welding-brazing method to weld 6061 aluminum alloy and galvanized steel,we could see that the obtained joint was welded finely and evenly. The morphology of the corrosion area of the welded joint was wider than that of the base metal. However,the corrosion polarization curve and the second half of the electrochemical impedance showed that the steel had poorer corrosion resistance and a faster corrosion rate. By-pass and metal inert gas （ MIG） arcs could form a coupling arc within the by-pass current and thereby change the force field distribution and heat input to the droplet and molten pool. This would result in the formation of welding and avoid welding defects. Different densities of the corroded area and different distributions of the elements are the main reasons for the different rates and degrees of corrosion. ur analysis of the influence of different microstructures on joint corrosion will provide a theoretical basis for improving the quality of welding joints in engineering applica-tions.