轧后冷却不均匀对板形影响研究

Research on the influence of uneven cooling after rolling on plate shape

目前唐钢2050热轧线在生产薄规格双相钢基料时在带钢头部出现了瓢曲、双边浪等板形问题,影响后续的生产。由于轧机出口板形合格率较高,所以将研究重点放在轧后冷却方面。通过对带钢FDT和CT横向温度比较,基本排除了层流冷却的影响。利用ABAQUS软件建立有限元模型,模拟带钢在卷取区域温度场-相变场-应力场的三场耦合过程中残余应力的变化情况,通过微观金相组织分析对模型的准确性进行验证,尝试分析了带钢在卷取冷却水的干扰下,造成相变不均匀而产生残余应力的机理。并提出了对卷取冷却水传统喷射时序进行优化的工艺方案,降低了部分残余应力并改善了残余应力的分布均匀性,使带钢头部板形瓢曲、双边浪的程度大幅下降,提高了下游冷轧生产效率及成材率。

At present,the 2050 hot rolling line of Tangshan Iron and Steel Company has encountered plate shape problems such as curling and double-sided waves at the head of the strip during the production of thin specification dual phase steel substrates,which affects subsequent production.Due to the high qualification rate of the exit plate shape of the rolling mill,the research focus will be on post rolling cooling.By comparing the transverse temperatures of FDT and CT strips,the influence of laminar cooling has been basically eliminated.A finite element model was established using ABAQUS software to simulate the variation of residual stress in the temperature field,phase transformation field,and stress field coupling process of strip steel in the coiling area.The accuracy of the model was verified through microstructure analysis,and the mechanism of residual stress caused by uneven phase transformation of strip steel under the interference of coiling cooling water was attempted to analyze.And a process plan was proposed to optimize the traditional spray timing of coiling cooling water,which reduced some residual stresses and improved the distribution uniformity of residual stresses.This significantly reduced the degree of strip head bending and double-sided waves,and improved the downstream coldrolling production efficiency and yield.