Numerical Approach on the Reproduce of a Strip End Flip Phenomenon in Finishing Mill

摘要

Strip end flip is an instability phenomenon in finishing rolling process. It often occurs upon steel strip end being released from the work rolls of a previous mill stand. Undesirable motion of steel strip such as side walk may cause strip hitting the side guides located at the entrance of a subsequent mill stand and result in a flip phenomenon of strip end. As a result, it may cause folding of the strip end and seriously damage the finishing roll surface. This would significantly deteriorate the strip quality and impede yield rate. Statistically, the occurrence of strip end flip is usually less than 5% during finishing rolling, yet due to lacking of regularity and difficulty in observation, this phenomenon has been a troublesome issue in finishing rolling. We intend to reproduce the strip end flip phenomenon by exploring a numerical simulation on a finishing mill model based on observation and on empirical on-site data collected from production line. By evaluating the effect of the parameters and the boundary conditions on the severity of the strip end flip, an interpretation of the phenomenon and on the possible mechanisms is explored. By tuning the roll alignment and by varying the degree of camber, a realistic reproduction of the strip end flip was realized. The simulated phenomenon was in good trend with the on-site video image. The strip end flip was mainly attributed to the effect of camber of the strip, the alignment of the rolls played a less significant role. The so far exciting outcome of the numerical simulation provides a feasible way to systematically explore the mechanisms of the strip end flip and to keep this problem under control.