ABSTRACT
The problem of determination of the parameters of preheating of the edges prior to flashing in reversing movement of the movable platen of the welding machine is investigated. The physical-mathematical model of pulsed preheating is described. The numerical solution of the equations of the model makes it possible to determine the optimum period of oscillations of the movable platen of the machine, upset force and the duration of closure of the welded joint, the supply voltage and the number of preheat periods. The optimum values were obtained for the duration of closure of the welded joint which is slightly shorter than the period of oscillations of the movable platen of the welding machine and the compression force, at which the electrical resistance of the joint is equal to the electrical resistance of the welding machine and the preheating time results in the temperature at which the hardness of the metal is equal to the pressure generated by the upset force of the welded joint.