| 摘要 |
PURPOSE:To efficiently carry out roll cooling while suppressing shape inferiority of steel strip, by winding heated and held steel strip to plural rolls in order in overlaid and contacted states, starting rapid cooling at a suitable temp., and suitably controlling tension of steel strip. CONSTITUTION:Steel strip heated and held in continuous heating treatment furnace is wound to plural rolls in order in ovelaid and contacted state and rapidly cooled in cooling process. At this time, the rapid cooling is started at 550-720 deg.C range. Accompanying with this, a tension (kgf/mm<2>) is adjusted to range of an inequality; (1,900-Ts)/1,670<alpha<(1,980-Ts)/720 according to a starting temp. Ts( deg.C) of the rapid cooling. In this way, uneven cooling over width direction of steel strip is suppressed to the minimum to effectively suppress shape inferiority of steel strip, and cooling capacity can be exhibited inexpensively to the maximum limit.
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