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

In this paper, S235JR(Cu) steel sheets were welded by electrical resistance spot welding method.Their thickness was 2 mm and joints were prepared in overlap joint form.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 periods 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.As a result of these experiments, the maximum tensile-shear and tensile-peel strength are obtained in 30 period welding time for 8.5 kA welding current.