The application of aluminum alloy, which is a typical lightweight material, has been expected to the construction of the transportation vehicle to achieve energy saving by reduction of its weight. However, the structure made of whole aluminum alloy had problems with low strength and high cost. Thus, hybrid structure made of Al alloy and steel is useful because of lightweight and higher strength. To construct the hybrid structure, it is necessary to weld between aluminum alloy and steel. However, the conventional welding methods, like brazing and mechanical fastening, have some problems such as low mechanical strength and low productivity. Also, it is difficult to weld Al alloy and steel by conventional fusion welding. In this study, spot welding between aluminum alloy and low carbon steel by friction stirring was carried out. Especially, optimization in welding conditions was carried out. Moreover, the effect of welding conditions on the joint strength and weld interface was studied. As a result, relatively higher tensile shear strength of the weld which was achieved at an optimum welding conditions was obtained. Temperature near weld interface measured by K type thermocouple during welding was found to be the value lower than the melting point of A5052. From the observation results on microstructure of weld interface, it was found that Fe/Al intermetallic compound layer was formed.
Spot welding by friction stirring between aluminum alloy (AA5052) and several kinds of steels was conducted. Several kinds of steels were mild steel (270MPa of yield strength), high tensile strength steel (HTS steel, 980MPa of yield strength). The variation of cross tensile and tensile shear strengths of weld joints has the similar tendency. After shown the maximum strength, both tensile strengths decrease with increasing plunge depth. Torque, vertical load and temperature measured during welding between AA5052 and HTS steel indicate a high value more comparatively in any measurements than another one measured during welding between AA5052 and mild steel. The plastic flow like a tornado in AA5052 is caused by combining some plastic flows that had different directions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.