| 摘要 |
PURPOSE:To stabilize strength by deforming the dimensions of ingot by performing hot forging before hot rolling when manufacturing a shape steel with a large-sized rectangular cross section. CONSTITUTION:When hot forging an ingot, the thickness dimensions to be hot rolled is formed so as to be larger than the thickness dimensions of the cross section at the time of the ingot so that a desired hot working ratio can be obtained in the following hot rolling process. Next, that forged material is hot rolled so that working ratio is af least >=50% and, after that, the removing treatment of oxidized layer is performed. And, it is worked so as to obtain the shape steel with the desired thickness in a rectangular cross section when performing cold rolling finally at the working ratio of 30-50%. In this way, the large-sized shape sheel with rectangular cross section which has homogenous and fine grain size and which has wholly stable strength can be obtained. |
