Effect of Input Heat of Resistance Spot Welding (RSW) Process on the Mechanical Behavior of Welded Joint of SS-۳۱۶L Steel

In the automobile sector, stainless steel and resistance spot welding (RSW) are often used. In this work, RSW was used to join five samples of ۳۱۶L stainless steel joints at currents of ۱۵, ۲۰, ۲۵, ۳۰, and ۳۵ kA while the heat input parameters varied. The welded joints' microstructure, hardness, and mechanical properties were examined and evaluated. The base metal, heat-affected zone (HAZ), and weld areas' microstructures were all examined using optical microscopy. The mechanical characteristics of the joints were assessed using room-temperature tensile-shear testing and hardness testing. The microstructure findings revealed ferrite in many weld regions and an austenitic structure overall. In the samples with welding currents of ۱۵, ۲۰, ۲۵, ۳۰, and ۳۵ kA, the average hardness of the weld zone was ۳۲۹, ۲۵۸, ۲۵۱, ۲۳۸, and ۲۳۵ Vickers, in that order. The hardness of the weld zone exhibited an inverse connection with the welding current, as an increase in welding current resulted in a drop in the resistance spot welded area's hardness. Furthermore, when heat input increased, the hardness of the HAZ reduced and increased relative to the ۳۱۶L steel. The joint strength of the RSW increased with increasing welding current, as demonstrated by the tensile-shear test results for all five welded samples with varying currents. As a result, the samples with ۳۰ and ۳۵ kA currents failed at the weld with a force greater than ۳ kN, while the other samples with lower welding currents had a failure force of less than ۲ kN.

کلیدواژه ها:

۳۱۶ stainless steel ، Resistance spot welding ، Input heat ، Mechanical behavior