Behavior of Microstructure, Mechanical Performance, and Corrosion Behavior of AISI 201 Under Varying Resistance Spot Welding Condition

Abstract This research focuses on evaluating how different resistance spot welding parameters influence the structural features, strength, and corrosion behavior of AISI 201 stainless steel. The parameters studied include welding current (9, 11, and 13 kA), electrode pressure (41.4, 48.3, and 55.2 KPa), welding time (20, 23, and 26 cycles), and shielding atmosphere (air, nitrogen, and argon). Experimental observations showed that higher welding current and extended welding time enhance both hardness and tensile shear strength. The optimal tensile performance (12.2 kN) was achieved using 13 kA, 48.3 KPa, 26 cycles, and nitrogen shielding, surpassing air and argon under the same conditions. Maximum hardness was also observed under nitrogen, reaching 353 HV, which is notably higher than the base metal. Microscopic analysis revealed that under low heat input, sound joints without visible defects can be formed. Despite this, welded zones demonstrated increased corrosion susceptibility compared to the base material. Electrochemical testing in a chloride-rich solution indicated that corrosion rates grow with increased current, whereas nitrogen shielding offered superior resistance. The best corrosion performance was recorded at 11 kA, 41.4 KPa, and 26 cycles in nitrogen, where the corrosion rate was significantly lower than in argon or air. These results underline the need for careful selection of process parameters to balance strength and corrosion resistance in welded stainless steel components.