Enhancing the Strength of Aluminum–Stainless Steel Spot Weld using Magnetic Pulses

In this paper, the magnetic pulse spot welding of aluminum and stainless steel sheets was successfully performed by placing a perforated insulator mask between the sheets. In order to improve the strength of spot welds, the parameters of voltage, thickness of mask, thickness of driver and diameter of mask hole were studied. It was observed that the increase in process parameters improved the tensile strength by 7.7 MPa and reduced the weld width by 62.5 µm. However, simultaneous enhancement of the tensile strength and weld width was achieved by setting the voltage at 11.86 kV, diameter of mask hole at 9 mm, thickness of mask at 1 mm and thickness of driver at 1 mm. The microstructure analysis indicated that the increase in process parameters resulted in the refinement of grain size up to 14 µm and formation of intermetallic layers Fe₄Al₁₃ and Al₁₃Cr₂. However, the interface of spot weld was found to be free of any intermetallic layers and defects at the optimal values of parameters.