RESISTANCE WELDING MONITORING METHOD AND RESISTANCE WELDING CONTROLLING METHOD

PROBLEM TO BE SOLVED: To provide a resistance welding monitoring method by which welding quality can be properly determined by accurately compensating influence of eddy current. SOLUTION: In the resistance welding monitoring method, an electric current applied between electrode tips 5, 6 and a voltage therebetween are measured, with a resistance value of a welded member calculated using the measurement, and then, on the basis of the calculation result, the welding quality of the welded member is estimated. Where V is a measured voltage, i is a measured current, R is an inter-electrode tip resistance in a short-circuited state, M is a mutual circuit inductance of the measurement and a welding machine, and L is the self inductance of the welding machine circuit; an equation V=i×R+(L+M)×di/dt is used for energization, setting a relational expression between (L+M) and R in the short-circuited state of the electrode tips 5, 6. The relational expression of M and R is used for welding, compensating the measured voltage influenced by the eddy current during the welding and, on the basis of the compensation result, calculating a welding voltage to be applied to the welded member. COPYRIGHT: (C)2008,JPO&INPIT