| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a hot rolling method of bar material for manufacturing a bar product which suffices rigid requirements in recent years for guarantee against surface flaws by preventing the occurrence of minute surface flaws caused by rolling deformation in the hot rolling process for bar materials such as wire rods, steel bars and square bars. <P>SOLUTION: In the hot rolling process of bar material, a billet as a raw material is sequentially reduced in its cross-section area by respective rolling process of passing through calibers of rollers disposed plurally and is finished to a prescribed size. The cross-section area of a rolled product is decreased so that compressive strain in the circumferential direction of the rolled product at the pass in the respective rolling process becomes not less than -0.5, and thereby a troublesome surface flaw, which may cause a processing defect in the succeeding process, is not produced by the rolling deformation, and it becomes possible to provide the bar product having excellent surface quality which can meet rigid requirements in recent years for guarantee against surface flaws. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
