高强度厚规格钢板板形控制研究

Research on shape control of high strength heavy plate

针对宝武鄂钢4 300 mm宽厚板轧机轧制高强度厚规格钢板出现的“搓衣板”和“蛇形弯”板形缺陷问题,对其产生原因进行了分析。结果表明:“搓衣板”板形缺陷的形成是由于轧机机架精度不够造成轧辊辊系不稳定,高强度钢板在轧制过程中上下表面金属变形不一致而导致的,同时由于钢板头部下扣,使钢板在轧制延伸时受阻,加剧了整板“搓衣板”板形缺陷的形成。轧机主电机负荷平衡功能的投入会干预到上下主电机速度的给定,造成钢板“蛇形弯”缺陷,同时由于轧机雪橇功能的过分使用会加剧该种板形缺陷的形成。为此,提出了加强轧机机架间隙精度的管理措施,有利于轧制过程中辊系的稳定;对钢板精轧阶段压下制度进行了优化,即末道次压下率为12%~17%时,可使钢板头部板形为单弧形上翘,不会产生“搓衣板”缺陷;对轧机主电机负荷平衡功能及雪橇功能进行了优化,减少了钢板咬入阶段上下主电机速度波动,有利于钢板头部“蛇形弯”的控制。上述措施实施后,厚规格高强度钢板板形明显改善,降低了生产成本,提升了宽厚板厂产品质量和市场竞争力。

In view of the shape defects of “washboard” and “serpentine bend” of high strength heavy plate in 4 300 mm wide and heavy plate line of Baowu Esteel, the causes were analyzed.The results show that the “washboard” shape defect is caused by the instability of the roll system, which induced by the insufficient accuracy of the rolling mill frame and the inconsistent metal deformation of the upper and lower surfaces of the high strength plate in the rolling process.At the same time, due to the buckle of the head of the plate, the plate is blocked in the rolling extension, which intensifies the formation of the “washboard” shape defect of the whole plate.The input of the load balance function of the main motor of the rolling mill will interfere with the given speed of the upper and lower main motors, resulting in the “serpentine bend” defect of the plate.At the same time, the excessive use of the sled function of the rolling mill will aggravate the formation of this kind of shape defect.Therefore, the management measures to strengthen the gap accuracy of the mill stand were put forward, which was conducive to the stability of the roll system in the rolling process.The reduction scheme in the finishing rolling stage of plate was optimized.When the reduction rate of the last pass was 12%-17%, the shape of the plate head can be single arc upward, and the defect of “washboard” would not be produced.The load balance function and sled function of the main motor of the rolling mill were optimized to reduce the speed fluctuation of the upper and lower main motors in the plate biting stage, which was conducive to the control of the “serpentine bend” at the head of the plate.After the implementation of the above measures, the shape of high strength heavy plate had been significantly improved, the production cost had been reduced, and the product quality and market competitiveness of the wide and thick plate factory had been improved.