| 摘要 |
<p>A steel for electron-beam welding joint includes as a composition, by mass%, at least C: 0.02% to 0.10%, Si: 0.05% to 0.30%, Mn: 1.5% to 2.5%, Al: more than 0.004% to 0.05% or less, Ti: 0.005% to 0.015%, N: 0.0020% to 0.0060%, P: limited to 0.015% or less, S: limited to 0.010% or less, O: limited to 0.0035% or less, and a balance consisting of iron and unavoidable impurities, wherein an index value CeEBB is 0.42% to 0.65%, a number of inclusion particles having an equivalent circle diameter of 1.0 µm or more is 20 pieces/mm 2 or less at a thickness center portion, and a number of nitride particles containing Ti of 10% or more and having an equivalent circle diameter of 0.05 µm or more and less than 0.5 µm is 1 × 10 3 pieces/mm 2 or more at the thickness center portion.</p> |
