| 摘要 |
PURPOSE:To prevent the generation of rolling flaws at outer surface of the flange in the longitudinal end zone, by executing the breakdown rolling with the caliber provided with the specified size of relief and increased cutting width, at the breakdown rolling for the H-beam blank with small breadth. CONSTITUTION:At the breakdown rolling for the H-beam blank with small breadth, in which the web height is larger than 600mm and the ratio of the web height to the flange breadth is larger than 2, Q is designated for the cross point between the extension line JO of the outer wall 12A of the caliber 12 and the horizontal extension KO of the outer edge 12B of the caliber 12, and P1 is designated for the point of contact between the caliber's corner and the straight line PL inclining 45 degrees against the horizontal extension KO of the outer edge 12B of the caliber 12, and the size of relief is designated as the horizontal distance (f) between P1 and Q being specified to 10-20mm; the breakdown rolling is executed with the caliber being thus increased in its cutting width. |
