| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-strength resistance spot welding joint that is prevented from peeling and fracturing and is not softened by reducing the segregation of nugget and making the occurrence of crack difficult to a group of two plates or more. <P>SOLUTION: The resistance spot welding joint for a thin steel plate is characterized in that, provided that the diameter of a nugget configured by the thin steel plate is d, a surface analysis is conducted to analyze the distribution state of an amount of P present on a region within the nugget enclosed by a closed curve having a distance of d/100 and a closed curve having a distance of d/5 in an inward direction of the nugget from an end of a fused portion on the horizontal surface of the nugget surrounded by corona bond, and an area ratio in which the density m (mass%) of P is more than twice as much as the density M (mass%) of P of a mother material composition is at 5% or less. <P>COPYRIGHT: (C)2013,JPO&INPIT |
