| 摘要 |
This H-shaped steel has a specific composition and contains oxide grains having a diameter of 0.005-2.0 μm, in terms of equivalent-circle diameter, in a population density of 100-5,000 grains per unit area of mm2. The oxide grains have a composition which comprises Ca, Al, and O, wherein, in terms of mass proportion relative to the components excluding the O, the Ca accounts for 5% or more, the Al accounts for 5% or more, and the sum of the Ca and the Al accounts for 50% or more. This H-shaped steel has flanges having a plate thickness of 100-150 mm, wherein the metallographic structure of each flange located in a position for strength evaluation has a bainite content of 80% or higher and the metallographic structure of each flange located in a position for toughness evaluation has an average prior-austenite grain diameter of 200 μm or smaller. |
