An improvement of the thermal model for producing the ultra-thin strips in a conventional hot strip mill

The production of ultra-thin strips is a new process being developed in hot strip mills to provide product substitution for certain similar cold-rolled products, the main advantage of this substitution being that the production cost in conventional hot rolling mills is lower than that in cold rolling ones. However, the production of ultra-thin strips is outside the conventional design scope of the traditional hot rolling process. One evident problem is that the thermal model implemented in traditional finishing mills supplies neither an accurate prediction of head-end temperature nor initiates correct action for strip´s in-bar temperature control. In this paper, a theoretical analysis of the heat transfer behavior for the hot-rolled strip in finishing stands was first investigated, and a simulation system was then developed as an off-line utility to evaluate the performance of the existing thermal model. Finally, an enhanced thermal model was proposed to match the requirement for producing ultra-thin strips in hot rolling mills, with both simulation and experimental results confirming that the setup accuracy of finishing temperature control is effectively improved.