| 摘要 |
<p>PURPOSE:To reduce defects in dimensional accuracy especially the offset of the center by determining the deviation between respective rolls by measuring the thicknesses and leg lengths of flange of the respective flanges in four upper, lower, right and lift parts of a roughly formed steel billet to which break down rolling is executed and changing roll positions based on this deviation. CONSTITUTION:The offset amount of the center of each of the right and left flanges is calculated from the thicknesses and leg lengths of respective upper, lower, right and left flanges of the roughly formed billet in the proximity region of a roughing universal mill. From conditions that the relationship of the difference between the drafts of the upper and lower flanges and the variation of the offset of the center, the target drafts of the flanges at the following pass and the mean draft of the upper and lower parts of the respective right and left flanges are equalized, the target thickness of flange on the outlet side at the following pass so that the offset of the center comes to zero or in the allowable range is determined. Based on this target thickness of flange on the outlet side, the deviation of the respective rolls 17, 18 of the roughing universal mill is calculated and, after the positions of the respective rolls are changed based on this arithmetic result, the billet is rolled by one or more passes.</p> |
