| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of hot-rolling by which a wire rod and a steel bar are made to properly bite into an oval caliber in such a state that the radius of a circular-arc portion of a rolled stock, which is brought into contact with the groove bottom part of a square caliber, is large to a degree that it is not the cause of generation of surface flaws in hot caliber rolling of the wire rod and the steel bar. SOLUTION: When expressing the radius of the circular-arc portion of the free surface of the rolled stock to be bitten into a square caliber on the outlet side of a diagonal caliber in a diamond-square-oval caliber schedule of the hot caliber system of the wire rod and the steel bar by r and the rolling reduction in the square caliber by (a), by preliminarily making the width dimension W of the rolled stock on the outlet side of the diamond caliber corresponded to the radius r of the circular-arc portion and predicting the radius r of the circular-arc portion from the width dimension W, a roll gap is set so that the ratio r/a is fallen in the range of 0.1-0.3, the width dimension W is measured during rolling, the radius r of the circular-arc portion which is preliminarily made to correspond is calculated from the measured width dimension Wa. When the ratio r/a is deviated from the range, the ratio r/a is made so as to fall in the range by adjusting the gap s of the caliber rolls just before the diamond caliber. COPYRIGHT: (C)2009,JPO&INPIT
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