Investigation of the effect of corrosion resistance on mechanical properties of electric spot resistance welded DP 980 steel sheets and stainless steel sheets

In this study, AISI 304–DP980 and AISI 304–galvanized steel sheets were joined by the electrical resistance spot welding method under a constant electrode pressure of 0.5 MPa; with welding currents of 8 kA, 10 kA, and 12 kA and welding times of 10, 15, 20, and 25 cycles (1 cycle = 0.02 s). The welded specimens were subjected to corrosion tests in 2%, 3%, and 4% saline solution environments. After the corrosion tests, mechanical properties of the corroded welded specimens were evaluated by tensile-shear force and average tensile-shear stress measurements, as well as microhardness measurements and microstructure examinations. Microstructure examinations revealed that the phases in the weld zone were different from the base metal, and the weld diameter increased with increasing welding parameters. The maximum microhardness value was observed in the weld zone with increasing welding parameters. Additionally, an increase in tensile-shear force and a decrease in average tensile-shear stress were observed with increasing welding parameters. As a result, since corrosion occurred on the surface and no corrosion formed in the weld core zone, the effect of corrosion on the mechanical properties of the weld zone remained limited, whereas the effects of welding parameters on mechanical strength were more pronounced. This study aims to evaluate the mechanical strength and microstructural properties of AISI 304–DP980 and galvanized steel sheets joined by electrical resistance spot welding in different saline solution environments