2250mm宽带钢热连轧生产线凸度控制优化

Optimization of Crown Control for 2250 mm Wide Strip Hot Rolling Production Line

首钢迁钢2 250mm热连轧生产线在达产初期出现了带钢凸度控制稳定性差的问题,甚至出现负凸度现象。对此热轧生产线的生产数据进行了分析,同时对轧辊温度与辊形进行了实际测量。究其原因为CVC辊形对热凸度和磨损辊形较为敏感,工作辊冷却水能力不足引起的轧辊热凸度过大破坏了CVC辊形曲线的板形控制能力。由于改造轧辊冷却水系统费用较高,需要停产,为了解决凸度控制稳定性问题,采用了辊形优化设计的方法。对精轧机组的CVC工作辊辊形进行了优化,空载辊缝凸度调控范围从[-0.7mm,0.7mm]增大到[-1.2mm,1.2mm]。同时,为了改善CVC工作辊与支撑辊辊间接触状态,设计并应用了CVC支撑辊辊形。此CVC辊形配置解决了首钢迁钢2 250mm热轧线凸度控制稳定性差的问题,板形控制精度由原来的67%提高到了93%以上。

There happened unstable problems of crown control and even negative crowns during the early in the production for reaching design annual capability in 2250mm hot strip mill of Qian＇ an Iron and Steel Company of Shougang Group. Data analysis of actual production and meanwhile the temperature and profile measurements of work rolls were carried out in this production line. The reason for the crown control problem was that CVC work roll contour was more sensitive to thermal and wear profiles and the big thermal crowns on CVC work rolls because of low capability of work roll cooling system destroyed the control capability of CVC on crown and in the end leaded to strips with small or negative crowns. Production was interrupted and cost for construction was higher if work roll cooling system were revamped. In the end, roll contour design and optimization were taken into account to solve the problem mentioned before. CVC work roll contour was optimized and the crown control range of unloaded roll gap was changed from [-0.7mm, 0.7mm] to [-1.2mm, 1.2mini. Meanwhile for improving the contact condition between CVC work and back-up rolls, CVC back-up roll contour was designed and applied. The unstable problem of crown control was solved after the new CVC roll contour configuration was used in the 2 250mm hot strip mill. The strip shape quality is improved and the shape control precision reaches to 93% above while the control precision before optimization is only 67%.