| 摘要 |
<p>PURPOSE: To provide the rolling method for a bar steel small in the rate of width change and diameter difference by setting inter-stand tension between 4-roll rolling mills on a compressive side and executing continuous rolling while imparting compressive stress in the axial direction to the bar steel. CONSTITUTION: When free tension rolling is executed by use of a free tension controller(FTC), a spreading rate is changed to the negative direction and narrowing is increased as the reduction of area is increased. However, by imparting the compressive stress to the bar steel by adjusting the rotational speed of the driving motor of a 1st stand mill so as to be slightly faster than that of the 2nd stand mill, the width variation of the bar steel is increased in the spreading direction in accordance with the increase of the compressive stress. By adjusting this compressive stress to be imparted to 0.05-0.30kg/mm<2> , the spreading change is decreased and the bar steel high in dimensional precision is obtained.</p> |
