| 摘要 |
<p>PURPOSE:To obtain a rolling method for steel material which can remarkably reduce a defect such as a porosity, etc., intrinsic in the central part of a billet. CONSTITUTION:When the rolling passes that the stain component of hydrostatic pressure acting on the central part of the steel material exceeds 6kgf/mm<2> in rolling the steel material are made at least one time or more, internal defects such as porosity, etc., are pressed and a remaining rate is reduced remarkably. When the steel material is cooled, then, rolled to enlarge the strain component of hydrostatic pressure and cooling conditions and rolling conditions are established so that the steel material temperature, the cooling speed, the cooling time and the rolling shape ratio satisfy prescribed conditions, steel material remarkably little in internal defects can be obtained.</p> |
