Method for Outlet Temperature Control during Warm Rolling of AZ31 Sheets with Heated Rolls

摘要

The warm rolling process with heated rolls for AZ31 sheets was proposed instead of normal hot rolling process without roll heating. Experimental study showed that the quality of rolled sheets was sensitive to the outlet temperatures which need well control during rolling process. In the paper, a computational model combining a finite element method (FEM) with a mathematical model was developed to predict the outlet temperature during the warm rolling of AZ31 alloy sheets. The accuracy of the FEM model was verified by rolling experiments with various process parameters. Numerous thermo mechanical finite element simulations were carried out to obtain a database relation between process parameters and out let temperature. The process parameters were rolls and sheet heated temperatures, rolling speed, initial sheet thickness and thickness reduction. The mathematical model was obtained based on regression of the database. The model gave satisfactory results when comparing the predictions and FEM simulation results. A comprehensive validation of the prediction model is presented by new set of designed experiments. In the explored process window, a good correlation was found with an error on the outlet temperature lower than 10°C. The proposed method in this paper was suitable for outlet temperature control by rolling schedule design during the warm rolling process of AZ31 sheet with heated rolls.