RESISTIVE SPOT-WELDING METHOD

WIPO Patent Application WO/2017/069268

A1

A resistive spot-welding method with which a welded joint having anti-delay-fracture properties can be formed, wherein the method is provided with a step for providing energization via an energizing current I1 (kA) while a welding pressure P1 (kN) is applied to a plurality of steel plates using a welding electrode, a step for providing energization via an energization current Ic (kA) over a cooling time period tc (s) while the welding pressure P1 is applied, a step for imparting a welding pressure P2 (kN) onto the plurality of steel plates using the welding electrode over a welding time period tf (s) while energizing the welding electrode with a conduction current I2 (kA) and immediately thereafter raising and lowering the welding pressure in two or more cycles in which a welding pressure P3 (kN) is applied over a welding pressure time period ti (s), a step for applying the welding pressure P2 over the welding pressure time period tf, and a step for releasing the welding pressure and ending energization, the steps being provided in the stated order. 0≦Ic