| 摘要 |
PROBLEM TO BE SOLVED: To provide a welded joint using a steel having excellent fatigue strength in a weld zone and having excellent cuttability.SOLUTION: A welded joint has a composition including, by mass, 0.02 to 0.20% C, 0.06 to 0.20% Si, 0.20 to 1.60% Mn, 0.010 to 0.033% P, ≤0.015% S, 0.03 to 0.08% Al, 0.01 to <0.5% Cu, 0.01 to 0.5% Ni and ≤0.009% N, and the balance Fe with impurities, and also satisfying 6≤20C+5Si+10Mn≤30, 0.01≤C/(Mn+(1/10)Cu+(1/2)Ni+(1/4)Cr+Mo+20Nb+10Ti+5V)≤0.10, P/Si≥0.12 and Al/Si≤0.60, and a metallic structure mainly composed of ferrite and bainite, and in which the area ratio of pearlite is ≤10%, and also, the half-value width of X-ray diffraction intensity from the (110) face is ≥0.13 degrees. |
