Welding Time Effect on Mechanical Properties in Resistance Spot Welding of S235JR(Cu) Steel Sheets Used in Railway Vehicles

This paper presents an experimental study on resistance spot welding of SPA-C steel sheets used in rail vehicles. SPA-C steel sheets having 2.3 mm thicknesses were joined by using resistance spot welding as lap joint. A timer and current controlled resistance spot welding machine having 120 kVA capacity and a pneumatic application mechanism with a single lever was used to prepare the specimens. Welding periods were chosen as 5, 10, 15, 20, 25 and 30 cycles and also welding currents were increased from 6 kA up to 14 kA by rise of 0,5 kA. The electrode force was kept constant at 6 kN. The obtained welding joints were exposed to tensile-peel and tensile-shear tests. Welding time effect on tensile-peel strength and tensile-shear strength were researched by using related diagrams and the optimum welding currents and times were advised.