Method For Manufacturing Spot Welded Joint, And Spot Welded Joint

Abstract: Provided is a method for manufacturing a spot welded joint, comprising: a regular welding step in which a regular welding current value Iw0 (kA) is supplied, so as to satisfy a predetermined condition, to a plate assembly comprising high-strength steel plates having a Ceq of at least 0.36% by mass, and a molten portion is formed thereby; a first subsequent power supply step in which a first subsequent power supply current value Iw1 is supplied for a time tw1 (ms) following a time tc1 during which power is not supplied; and a second subsequent power supply step in which, after the first subsequent power supply step, a current value Iw2 is supplied for a time tw2 following a time tc2 during which power is not supplied. The steps from the regular welding step to the final subsequent power supply step are carried out continuously in a state in which a pressurizing force FE is maintained. Further provided is a spot welded joint in which the number ratio of crystal grains having an aspect ratio of 7 or more is 50% or less in an intermediate portion in the longer-axis direction of a nugget.

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