Increasing resistance point welding quality of grill wires used in the kithcen oven industry

Electric resistance spot welding is one of the most important joining methods used in a wide area such as white goods, automotive and defense industry. In resistance spot welding, the biggest advantage of the method is that there is no need for filler metal, it is a suitable method for automation, it is a less risky and relatively clean and environmentally friendly process in terms of work safety. In this study, Ø6.5 mm and Ø2.3 mm low carbon and low silicon SAE 1006 quality wires were welded with resistance spot welding using 2 different electrode materials and different welding parameters (welding time and welding current). The maximum tensile strength of the welding joints was determined, the microstructures were examined and the lifetimes of the electrodes were compared with each other by welding with the optimum parameters. The welds are made using a current controlled and timed industrial resistance spot welding machine (HKTM) operating at 1000 Hz with a capacity of 40 kA and controlled by a programmable logic controller (PLC). Optical examination of welded products was carried out using Nikon brand microscope. Chatillon brand dynamometer was used to measure the maximum tensile strength. Mitutoyo brand gauge was used to measure the deformation of the electrodes. Welding times required in terms of maximum tensile strength and quality of weld seams of grid wires in welding studies were found separately for each electrode in this study. For example, the best welding parameters are 12 ms at 9 kA for CuCoBe electrode and 16 ms at 9 kA for CuNi3Si electrode. This difference can be attributed to the electrical conductivity of the electrodes. In addition, the most suitable electrode material was tried to be determined in terms of the amount of deformation in the welding electrodes. The CuCoBe electrode underwent less deformation than the CuNi3Si electrode at the same oppression number. However, the deformation rate of both electrodes was within acceptable limits in terms of weld quality. In the light of these results, electrode cost analysis was also performed and it was concluded that the most suitable electrode material in terms of minimum part cost was the CuNi3Si electrode.