Development of hot rolling practices for lithographic sheet using a thermo-mechanical and microstructural model of a reversing hot finishing mill

Commercial purity AA1050 alloy, which is used for lithographic sheet, is mostly hot rolled using a conventional hot-line consisting of a reversing hot breakdown mill and a tandem hot finishing mill (HFM). The production of lithographic sheet using an alternative hot-line with a single stand (reversing) HFM which requires less capital cost is examined. A model of the single stand HFM (with front and rear coilers) was developed to predict the thermo-mechanical histories and the Zener–Hollomon parameter. Microstructural relationships were incorporated into the model to evaluate the effects of different rolling conditions and thermo-mechanical histories on the recrystallisation behaviour. The model was validated with experimental results and then used to develop suitable hot rolling practices for lithographic sheet. Simulations of hot rolling showed that process conditions could be altered to minimize partial recrystallisation and to promote a more homogeneous microstructure. Favourable rolling practices can be readily determined, thereby reducing the need for expensive and often ad hoc plant trials.