| 摘要 |
PURPOSE: A welding joint with excellent fatigue characteristics is provided to use a steel material, which does not require any special management, as a base material, and to have excellent operability during welding and excellent fatigue characteristics. CONSTITUTION: A welding joint with excellent fatigue characteristics contains in mass%: C: 0.01-0.06%, Si: below 1.0% (including 0%), Mn: 1.25-2.5%, Cr: 0.1-2.0%, Mo: below 1.5% (including 0%), V: below 0.04% (including 0%), Ti: 0.005-0.030%, B: 0.0006-0.005%, P: below 0.02% (including 0%), S: below 0.01% (not including 0%), N: 0.0020-0.010%, and at least one kind selected from a group composed of Cu:0.01-2.0% and Ni: 0.01-5.0%. The residual quantity is Fe and inevitable impurities. The metal structure contains ferrite and bainite at an area rate of 90% or higher. The welding joint uses a steel material which satisfies mathematical formulae 1 and 2 below. However, [] in the formulae 1 and 2 indicates the content (mass%) of each element. |
