Spot Welded Joint And Method For Manufacturing Spot Welded Joint

Abstract: Provided is a spot welded joint, in which, in a cross section in a plate thickness direction of a plate set in which two or more steel plates are stacked, the steel plates including at least one steel sheet having a C content of 0.280-0.700 mass%: the average of the short diameters of prior austenite particles, the long diameters thereof, and ratios (long diameter/short diameter) of the long diameters to the short diameters is in the range 1.0-1.5 in a melting boundary region, which is a region extending 1 mm inward from a melting boundary at a nugget end section; and the number density of an iron carbide having, at the melting boundary region, an average circle equivalent diameter of 30 nm or greater is 3.0×106×C content (mass%) or greater per 1 mm2. The plate set in which the C content of at least one steel plate is 0.280-0.700 in terms of mass% is subjected to spot welding under specific conditions, and subsequently, tempering thereof is performed under specific conditions.

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