DROF工艺中轧件头尾温差与组织性能均匀性控制

棒线材免加热直接轧制(DROF)工艺有一个难以避免的问题,即轧件头尾温差问题。当轧件头尾温差较大时,会对产品组织性能均匀性产生不利影响。本文讨论了由于轧件头尾温差带来的产品组织性能波动范围,分析了在铸坯切断、送到轧机入口处、上冷床等几个特殊时刻,轧件沿纵向的温度分布特点。为了解决轧件头尾温差问题,提出采用精轧机组前变水量冷却、粗轧机组前变功率感应补热、切坯台加变长度保温罩等3种方式,以有效减小免加热条件下轧件头尾温差,控制其组织性能差异,获得质量优良的产品。

Temperature difference on head and tail of billet and control for homogeneity in microstructure and properties of products in DROF process

The temperature difference at the ends (head and tail) is a hard problem in DROF process.When the temperature difference is big,it would lead to have a bad influence on the homogeneity in microstructure and properties of the products.The fluctuation range of the microstructure and properties by DROF technology was discussed.The temperature distribution along longitude at the cut-off point,the roughing mill and the cooling bed were analyzed.Three different ways were proposed in order to solve this problem,that is changeable cooling water used at the entrance of finishing train,changeable induce heating system used before the roughing mill and changeable heat cover used at cutting platform.All of them were useful to reduce the temperature difference on the work piece,so as to produce products with good quality.