RESISTANCE WELDING METHOD, RESISTANCE-WELDED MEMBER, RESISTANCE WELDER AND CONTROL APPARATUS THEREOF, CONTROL METHOD AND CONTROL PROGRAM FOR RESISTANCE WELDER, AND RESISTANCE WELDING EVALUATION METHOD AND EVALUATION PROGRAM

摘要

PROBLEM TO BE SOLVED: To stabilize the quality of resistance welding even if various disturbances exist.SOLUTION: A resistance welding method includes: a melting start time specification process for specifying a melting start time, which is the time when at least a part of a welding portion (Y) of a welding subject (W) starts to melt while being subjected to Joule heating by a power inputted from an electrode (11) pressed against the welding subject (W), by detecting a variation in an ultrasonic wave emitted toward the welding portion; a first power amount calculation process for calculating a first power amount, which is an integrated value of the power inputted into the welding subject via the electrode from the melting start time; a first determination process for determining whether or not the first power amount has reached a first set value; and a heating process for performing the Joule heating from the melting start time until the first power amount reaches the first set value. The melting start time is specified accurately by detecting amplitude variation in the ultrasonic wave; and welding quality can be stabilized even if the disturbances exist by controlling electric energy after the melting start time.