Investigating the effect of electromagnetic impact welding parameters on the microstructure evolution and mechanical properties of SS-Cu joint

In the present research, the desirable values of electromagnetic impact welding parameters such as spacer distance, standoff distance and voltage were estimated to improve the mechanical properties of the dissimilar joint between stainless steel and copper. The numerical and experimental techniques were applied to perform the electromagnetic impact welding process using the response surface methodology. The microstructure and quality of the joints were assessed by tensile test, hardness test, scanning electron microscopy, X-Ray diffraction analysis and energy dispersive X-ray spectroscopy. The results indicated that an increase in voltage from 11.5 to 12.5 kV led to an enhancement in the hardness and tensile strength by about 6.7% and 7% respectively, while the weld length and elongation reduced by about 45.5% and 39.6% respectively. Moreover, the values of hardness and tensile strength improved by 3.4% and 4.3% respectively when the standoff distance increased from 1 to 2 mm. However, the increase of standoff distance from 1 to 2 mm indicated a reduction in the weld length and elongation by 6.6% and 12.5% respectively. The mechanical properties of the weld joint were improved simultaneously at a spacer distance of 1.8 cm, standoff distance of 2 mm and a voltage of 12 kV. The microstructure analysis showed that the initiation of crack in the intermetallic phases and the entrapment of oxides in the weld joint were responsible for reduction of the weld quality.