The Influence of Parameters of the Resistance Projection Welding of M10 Steel Nuts to the Galvanized Steel Sheet DP 600 on Selected Joint Characteristics

Projection welding belongs to the group of resistance welding technologies. The basic process parameters are the welding current and the current flow time. The resistance projection weldability of the fasteners on metal sheets is not as well understood as the resistance spot weldability of the sheets, so complex studies for the wider application of resistance welding of nuts in the automotive industry are still needed. This research is aimed at valuation the effect of resistance projection welding parameters (steel nuts on galvanized steel sheet DP 600) on joint properties. The hard welding mode ( high welding current, clamping force and short welding time) provided 2 times higher strength of the weld joints as the soft welding mode. When using the soft welding mode, an increased Zn concentration from the sheet metal coating was measured in the transition area between the welded materials at the folding locations. When applying the hard welding mode, only a slight increase in the Zn concentration was observed at the inner boundary of the weld joint.