Research status of copper/steel dissimilar metal welding

Several common welding methods for joining of copper-steel dissimilar metals at home and abroad were introduced emphatically. Based on characteristics of different welding methods, forming mechanism, microstructure and mechanical properties of welded joints were analyzed, and the existing problems and solutions of different welding methods were summarized systematically. For fusion welding, getting a more uniform melt pool to control segregation was the way to get a reliable joint. Traditional arc welding could be achieved by controlling filler material, while high-energy beam welding could take advantage of its precise control and use beam segregation or cyclic motion to get a more uniformly organized joint, which was a more reliable fusion welding method. For brazing and welding-brazing, selecting a suitable brazing material was the key to achieve a reliable connection, but mechanical properties of welded joints were generally poor and not suitable for application in load-bearing structures. In contrast to fusion welding, solid-phase welding did not involve melting of material and had a much finer and more uniform microstructure, making it a welding method with great potential. Regulating the formation of its interfacial reaction layer was a feasible way to further improve strength of welded joints. On this basis, prospect of future development direction of copper/steel dissimilar metal welding was put forward, and possible directions for future research on the above mentioned welding methods were presented.