The Shanghai Institute of Optics and mechanics uses resistance spot welding lase

Recently, the research and development center of laser intelligent manufacturing technology of Shanghai Institute of Optics and precision machinery, Chinese Academy of Sciences has carried out experimental research on resistance spot welding laser hybrid welding technology for aluminum / steel dissimilar metals, which has improved the mechanical properties of aluminum / steel dissimilar metal welded joints.

Relevant research results were published in Materials ＆ Design with the title of "Hybrid resistance－laser spot welding of aluminum to steel dissimilar materials： Microstructure and mechanical properties”.

Aluminum / steel dissimilar metal welding technology has a wide application prospect under the background of automobile lightweight. However, due to the great difference in thermophysical properties between aluminum and steel, a large number of brittle intermetallic compounds and cracks are formed in the weld during welding, which leads to the failure of aluminum / steel dissimilar metal welded components to meet the requirements of vehicle body application. So far, in order to solve the problem of aluminum / steel dissimilar metal welding, the past research work mainly focused on the optimization of welding parameters and the control of weld alloy elements, aiming at reducing the formation of brittle intermetallic compounds in the weld and improving the mechanical properties of the joint. However, at present, high-quality aluminum / steel dissimilar metal welded joints that can be widely used have not been obtained.

In view of the poor performance of Dissimilar Metal Welds of aluminum / steel, the researchers used a resistance spot welding laser hybrid welding technology to weld the combination. Firstly, spot welds are manufactured by resistance spot welding technology, which is the mainstream in automobile manufacturing, and then ring welds are manufactured around the spot welds by laser flying welding technology. By changing the structure of the weld joints and controlling the thickness of brittle intermetallic compounds, the mechanical properties of aluminum / steel joints are significantly improved. This work provides a new technical scheme for aluminum / steel dissimilar metal connection.

Relevant work has been supported by the industrial strong foundation project of Shanghai Economic and Information Commission.

Fig. 1 microstructure and element distribution of laser weld

Fig. 2 microstructure and element line distribution of aluminum / steel interface

Source: Shanghai Institute of Optics and precision machinery, Chinese Academy of Sciences