Effects of Electrode Deformation on Carbon Steel Weld Geometry of Resistance Spot Welding

The growth of the weld nugget is determined by the welding current, weld time, electrode force; and the electrode tip in resistance spot welding process. The welding current and weld time lead the heat development between base metals while the electrode pressing force and electrode tips’ ensures the molten areas are kept enclosed. As such these four process parameters are the main parameters that ensure a sound weld. In this research the electrode alignment during welding process and mushrooming effects of electrode tips are analysed using carbon steels. A pair of truncated-type electrodes was used to weld around 900 pair of test specimen. Some of welded pairs were stainless steel and it was not included here. The electrode deformation effects on the surface of carbon steels are primarily analysed in this research. It shows that the electrodes mushrooming effect are creating spaces for the molten metal to escape from the concerned areas during welding process. So the electrode deformation and alignment have simply created spaces for the expulsion; because of which the inconsistent weld surfaces were noticed. In fact the welding heat is actually affecting the electrode tips and the electrode tips itself are affecting the weld surface as well as weld nugget geometry.