A Multi-Objective Model for Sequencing Slabs in Hot Rolling Case study: Mobarekeh Steel Complex, Isfahan, Iran

Abstract

Optimizing steel slab transfer from the storage area to the hot rolling and their sequencing process is an inevitable problem. To partially solve this problem, a mathematical model is proposed based on the Travelling Salesman Problem (TSP). The coffin-shaped configuration of the slabs to be fed for one rolling unit is of concern. Kosiba's coffin-shaped configuration evolved in 1992 to prevent the probable damage to the slabs selected to be rolled. In this newly introduced multi-objective model, applied in Mobarakeh Steel Complex, Isfahan, Iran, all the metallurgic features and width of each slab are involved. These features are weighted to justify the subject configuration. For this purpose, several sensitivity analyses are run by giving the slab width more weight. To accomplish this, the distance between the adjacent slabs should be reduced. The results show that the arrangement of the slabs is in the best condition by assigning a weight of 0.8 to the width and 0.2 to the quality of the slabs, respectively, with penalty values of 1278 and 9280, which justifies this capability and the application of the model in better decision-making in management concepts.