PSI- Issue 9

Mohammad Jameel Zedan et al. / Procedia Structural Integrity 9 (2018) 37–46 Mohammad Jameel Zedan, et al./ Structural Integrity Procedia 00 (2018) 000–000

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Fig. 1. Lap joint configuration.

3. Results and discussion RSW of aluminum alloys into steel alloys is not easy due to the variation in physical and chemical properties. One of the most important differences between aluminum alloys and steel alloys is the expansion coefficients. The distortions occur due to the high temperature generated by the high amperage welding current on the aluminum side. Figure 2 shows the thermal expansion loop wave on the steel and aluminum side.

Fig. 2. The thermal expansion waves; (a) steel side; (b) the aluminum alloy side.

3.1. The new method To obtain successful welding between these two metals, the drilling method has been invented to overcome the problem of thermal expansion. A hole is drilled in the center of the overlapping area on the aluminum side below the contact points of the electrodes. When temperatures rise during the welding process, the thermal expansion will fill the punctured hole and prevent the deformation or expand in the aluminum alloy. The advantages of the new method are as follows:  The uniform weld area will be obtained.  The welding area will not damage due to the concentration of the welding current. Hence, the transmission of the current area will be circular. That increases the welding strength.