| 摘要 |
PURPOSE:To obtain a steel bar perfectly free from internal defects without enlarging the scale of rolling-mill equipment, by adding a forging stage, in manufacturing a steel bar by hot rolling after heating an ingot or a continuously cast bloom, and blooming the heated one. CONSTITUTION:After heating an ingot or a continuously cast bloom 1 in a heating furnace 2 and blooming the heated one; a steel bar is manufactured by performing a hot rolling containing an intermediate rolling and a finish one. Here, for instance, a rolling stage is interposed between the heating and blooming stages, to forge the heated bloom 1, etc. throughout its whole length by a forging machine 4. Or the forging can be performed after the blooming or by an optional roll stand during hot rolling. By this process, the weakness of internal-quality improving action by roll-rolling is reinforced by the forging, and a steel bar of good quality free from internal defects is obtained by a roll rolling of small reduction ratio. |
