| 摘要 |
PURPOSE:To manufacture high strength steel or a high strength steel wire at a low cost, by recuperating and heating a steel casting piece wound like a coil, in a prescribed temperature area, and after that, executing warm rolling of a specific draft or higher in said temperature area, and subsequently, executing its recrystallization annealing. CONSTITUTION:A casting piece is wound like a coil, and in a recuperative furnae, the whole coil is uniformly recuperated to 100-700 deg.C by utilizing sensible heat which the coil has. Subsequently, the coil which has been wound and recuperated is subjected to warm rolling whose cumulative draft is >=50% at <=700 deg.C, preferably, within a range of 200-600 deg.C, without passing through a regular hot rolling process. Subsequently, the casting piece which has been warm-rolled is subjected to hot rolling at <=700 deg.C, preferably, within a range of 200-600 deg.C. After that, the casting piece which has been warm-rolled is subjected to recrystallization annealing at a temperature of 750-1,150 deg.C, by which an object steel material having fine grain structure is obtained. |
