Analysis and Optimization of Material Flows in a Steel Plant Warehouse.

Efficient material handling and warehouse management are critical aspects of steel production plants, where a large number of billet movements are performed daily across internal and external storage areas. Inefficient logistics decisions can lead to unnecessary relocations, increased handling costs, and reduced operational performance. This thesis presents a data-driven analysis of billet movements in the warehouse of an industrial steel plant. The objective is to understand the behavior of the current system and identify the main sources of inefficiency in the storage and retrieval operations. The analysis highlights how the fragmentation of different steel grades — i.e., steel types defined by their chemical composition and metallurgical properties — across multiple stacks generates a significant number of additional movements, for example during destacking operations required to access buried billets. To address this issue, a storage reorganization strategy based on dedicated stacks for steel grades is proposed. Stack allocation is determined through a scoring mechanism that considers both the maximum number of billets simultaneously present in the system and the average residence time of each grade in the warehouse, allowing the identification of high-rotation and low-rotation materials. Based on this score, frequently accessed grades are assigned to stacks in the internal warehouse, while less frequently used grades are allocated to the external storage area. Starting from the latest observed state of the warehouse, a procedure is then developed to reorganize billet positions according to the dedicated stack configuration while minimizing the number of required movements. The approach exploits available buffer locations to reduce unnecessary relocations during the reorganization process. The results show that a structured storage policy based on dedicated stacks can significantly reduce avoidable movements caused by grade fragmentation, improving the efficiency of warehouse operations and providing useful decision support for warehouse management.