ELECTRIC CURRENT WAVEFORM DETERMINATION METHOD ON RESISTANCE SPOT WELDING AND RESISTANCE SPOT WELDING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an electric current waveform determination method in resistance spot welding, capable of determining an electric current waveform which enlarges a proper electric current range.SOLUTION: An electric current waveform determination method in resistance spot welding includes a process for solving such an optimization problem in which it is set as an object function that S which is an integral value of DN(t) at a time t=0 to is maximum and DN() is maximum, it is set as a constraint condition that Fas the minimum value after nugget formation start at a time of F(t) t=0 to has a relation of F(1-k)*P and an electric current waveform IS(t) is design variable, when a stacked body constituted with a plurality of materials to be welded is held between a pair of electrodes and an electric current waveform on resistance spot welding for joining the plurality of material to be welded is determined, when a pressure applied from the electrodes to the stacked body is P, an electricity conduction time is , a nugget diameter at the time t taken from any value of 0 to is DN(t), a coefficient taken from any value of 0 to 1 is k and a force at the time t acting on a non-melt part is F(t).