A hierarchical approach for the application of slabs to strip products in the steel industry

In the mid-1990s, the Sparrows Point Steel Plant began an initiative to achieve 100% on time slab availability to the hot strip mill. At that time, order dressing, heat building, slab application, and mill scheduling of strip product orders were manually intensive activities. It was decided to implement an integrated system to automate these activities. In this paper we discuss the central activity of this system – the application of slabs to strip product orders (used for appliance panels, steel storage sheds, food cans, etc.). A binary integer linear programming formulation will be given for the slab application problem. However, because of the size of typical problem instances, a robust and efficient hierarchical heuristic solution approach was developed that has been in daily use since 1999.