The mechanism of the position-mode side guide in correcting slab centerline profile and camber in the roughing process of a hot strip mill (HSM) was analyzed using finite element simulation. The finite element model was established based on the actual size of the roughing mill and on the actual actuating time sequence of the roughing mill in China Steel Corporation (CSC), Kaohsiung. This work could be the first to give an insight into the mechanism of side guides in correcting the slab camber. Time sequence analysis was explored to visualize the progress of centerline profile variation and the interaction between the slab and the related roughing mill components at different moments. The history of reaction forces exerted on the slab was analyzed to explain the interaction between roughing mill components and the slab. The effect of the separation distance of side guide and the effect of the slab wedge on the centerline profile was investigated. A schematic model illustrating the reactions and the resulting moments exerted on the slab was created. By examining the force history, the cross-sectional strain/stress distribution, and the roll force across the horizontal roller, the correcting mechanism of the side guide could be elucidated. The simulation results provide further knowledge in selection and dimension design of side guide to improve the effectiveness of side guide in correcting the slab profile.

The process stability of finishing mill is significantly influenced by the clearance between the chocks and housing in mill stands. The on-site data of a finishing mill had shown that the clearances in the finishing mill stands were clearly associated with the incidence of strip end flip. The aim of this work was to establish a numerical model to analyze the effect of the clearances on the deviation of the centerline of the strip and on the incidence of strip end flip. By adopting conditions from a particular strip, the numerical model not only predicted the strip end shape, but also visualized strip end flip, which would be otherwise invisible. Four different degrees of asymmetry regarding work rolls and backup rolls were postulated. It was found that the degradation of the work rolls’ clearance level was the most significant influence on the centerline deviation of the strip. Strip end flip was most susceptible to the degradation of the horizontal clearance of the work roll. The simultaneous degradation of the work rolls’ and backup rolls’ level of clearance led to larger reactions and enhanced the asymmetric wear on the liners. The superimposed axial clearances at the roll end provided an axial constraint to the work roll, and were able to reverse the trend of centerline deviation. The numerical results provided a guideline for designing a suitable maintenance strategy for clearances.

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