Patent ID: 11592045

Abstract:
A lap fillet arc welded joint includes: a first steel sheet and a second steel sheet which are overlapped each other, the first steel sheet and the second steel sheet each having a tensile strength of 950 MPa or more; and a weld metal which extends along a corner formed by an upper surface of the first steel sheet and an end surface of the second steel sheet. When: a toe angle of the weld metal is defined as β; the total number of concave portions present on the surface of the weld metal included a range of 0.4 mm or less from a fusion boundary is defined as NA; and the number of concave portions in contact with ferrite grains having a maximum grain size of 10 μm or more is defined as NB, the weld metal satisfies the following conditional expressions (1) and (2) at the same time. 0°<β<30°  (1)NB/NA≤0.70  (2) (Here, NA is 20 or more).