Characterization of electrical contact conditions in spot welding assemblies

In this study the interfacial conditions encountered in electrodes and sheets assemblies used in resistance spot welding process are characterized. Electrical contact resistances are measured on a specific device, allowing to rise high pressure and elevated temperature. Measurements concern electrode–sheet (E/S) and sheet–sheet (S/S) interfaces, considering coated and non-coated steel sheets. The evolutions of the electrode profiles according to the number of weld are presented. The quick wear of the electrodes surfaces is also measured, depending on the type of sheets (coated or none coated). A numerical approach is chosen to simulate the squeezing stage, to show the consequences of modifying the electrode profiles on the initial contact surfaces at the beginning of the heating stage.