| 摘要 |
<p>An inclusion, the major diameter of which is 3.0 µm or greater in a cross section having the plate width direction of a high-strength hot-rolled steel plate as the normal, wherein the maximum value of the major diameter/minor diameter ratio represented by (the major diameter of the inclusion)/ (the minor diameter of the inclusion) is 8.0 or less, and the sum of the rolling direction length per 1 mm2 cross-section of a predetermined inclusion group consisting of a plurality of inclusions, the major diameter of which is 3.0 µm or greater, and a predetermined extended inclusion, the length in the rolling direction of which is 30 µm or greater is 0.25 mm or less. The plurality of inclusions constituting the predetermined inclusion group are clustered at an interval of 50 µm or less with one another in both of the rolling direction and a direction perpendicular to the rolling direction. The predetermined extended inclusion is spaced at an interval of exceeding 50 µm from all inclusions, the major diameter of which is 3.0 µm or greater in at least one of the rolling direction or the direction perpendicular thereto.</p> |
