| 摘要 |
PURPOSE:To maintain the crown of a cooling roll in a flat state from the start till end of charging of a molten metal by exerting an internal pressure on the central part of the roll prior to start of the charging and increasing the internal pressure in both edge parts of the roll after the start of the charging. CONSTITUTION:The surface of a cooling sleeve 11 is ground by as much as the heat crown rate to be generated by a heat attack prior to start of charging a molten metal. The liquid pressure equal to the liquid pressure in the stage of grinding is exerted only on the central part of the sleeve 11 in the stage of starting the charging to expand the outside circumference and to maintain the roll crown in a flat state, then the charging is started. The heat crown is going to arise in the sleeve 11 on account of a heat attack after the start of the charging but the liquid pressure in both edge parts is increased while the liquid pressure exerted in the central part is decreased according to the thermal expansion in the central part. The thermal expansions are thus effectively offset and the crown of the sleeve 11 is maintained always in the flat state from the start till the end of the charging. |
