Selecting optimal ingot sizes for Bethlehem steel

To take maximum advantage of a new ingot mold stripping facility, which was installed in 1984 at the Bethlehem Plant, the authors developed a two-phase, computer-based procedure for selecting optimal ingot dimensions and internal ingot mold dimensions. Phase 1 generated feasible ingot and internal ingot mold dimensions consistent with the new stripper’s capability and with foundry, steelmaking, metallurgical, mill, and shipping yard constraints. Phase 2 then used a set-covering approach to select the optimal ingot and internal ingot mold sizes from among the feasible sizes. Based on model results and following trial mill tests, full production use of new mold sizes has affected the entire plant operation, resulting in over $8 million annual realized savings.