| 摘要 |
<p>PROBLEM TO BE SOLVED: To materialize a hot-rolled coiled material having soft and uniform structure by properly cooling a coiled material wound after being hot-rolled.SOLUTION: A method for cooling a hot-rolled coiled material of the present invention is a method for cooling a coiled material S obtained by winding a rolled material W subjected to hot rolling. The method for cooling the hot-rolled coiled material comprises the step of : winding the rolled material W to the coiled material S at a winding temperature CT equal to or higher than a temperature TA determined based on a bainite transformation temperature determined by a steel grade component of the rolled material W; obtaining a retention time ta taken until the coiled material S becomes a ferrite perlite structure, based on the steel grade component of the rolled material W and the winding temperature CT; calculating a temperature drop situation of an outer circumference part of the coiled material S by performing heat transfer calculation on the coiled material S, thereby obtaining a time tb taken until the coiled material S becomes a martensite transformation temperature TB or lower determined by the steel grade component of the coiled material S, based on the calculated temperature drop situation; and keeping warm the coiled material S before the time tb elapses after winding the coiled material S, when the time ta becomes longer than the time tb.</p> |
