Manufacturing method for spot welded joints

Abstract

A method for manufacturing a spot-welded joint that can suppress hydrogen embrittlement cracking when forming a small-diameter nugget in a plate assembly including high-strength steel plates and that requires a short time for welding is provided. [Solution] A manufacturing method for a spot welded joint according to one embodiment of the present disclosure includes a step of forming a nugget in a plate assembly consisting of two stacked steel plates of the same type and thickness, wherein the tensile strength of the steel plates is 1400 MPa or more and satisfies 1.0≦t≦2.0, 0.8≦G, 2.8√t≦D≦3.5√t, (10t+12) / 60≦T≦(10t+30) / 60, and 2000t≦P, where t is the thickness of one steel plate, G is the thickness of the gap between the two steel plates just before the welding current is applied, D is the diameter of the nugget, T is the duration of the welding current flow, P is the pressure applied when the welding current is applied, and the time required for the temperature of the region corresponding to the end of the nugget to reach 1450°C or higher and 1500°C or lower is 50 msec or longer.

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