| 摘要 |
Provided is a spot-welded joint (10) in which at least one thin steel plate has a tensile strength of 750 MPa to 1850 MPa and a carbon equivalent Ceq between 0.22 % by mass and 0. 55 % by mass inclusive and a nugget (3) is formed at an interface between the thin steel plates (1A, 1B). In a nugget outer layer region of the spot-welded joint, the microstructure is composed of a dendrite structure of which an average interspace of arms is not more than 12 μm, and the average particle diameter and the number density of carbides contained in the microstructure are 5 nm to 100 nm and not less than 2 x 10<sup>6</sup>/mm<sup>2</sup>, respectively. |
