| 摘要 |
PURPOSE:To obtain a rough shape steel ingot having a large height of a web by rolling down only the web in the root end part in the rolling direction of the ingot to increase the height of the web then rolling down the web over the entir length and preventing the generation of deformation of web in the steel ingot. CONSTITUTION:First a beam blank is rolled by calibers 14 to an intermediate rough shape steel ingot 17 to decrease the leg length h1 of flanges. Thereafter only the web is screwed down with calibers 15 to increase the height of the web from H1 to H2 and to decrease the thickness t2 of the web. Further the ingot is rolled with calibers 16 to an H-shaped rough shape steel ingot 12. In the stage of rolling only the web with the calibers 15, swimming tends to arise on the right and left; therefore manipulators 22, 21 are provided on the inlet side and outlet side of breakdown rolls 13 and the ingot 18 is positioned so as to be gnawed into the calibers 15 at the preceding pass width L0 of the manipulator 21. When the root end part of the ingot 18 arrives at the inlet side manipulator, the guidin widths of both manipulators 21, 22 are set at the guiding widths L adaptable to the height L2 of the outlet side in the next pass, and the ingot is rolled over the entire length from the preceding end part in the rolling direction. |
