Product variety, flexibility and energy use in hot rolling mills

Abstract

Hot rolling consumes one third of the energy in a steel plant. Increasing product variety slows down production flow, causing heat losses and increased reheating energy consumption. A system dynamics model was developed to evaluate how flexibility influences energy use. Results indicate that world best practice requires high flexibility and low to intermediate product variety. Up to 28% less reheating was needed for low product variety, but no improvement was obtained for high product variety; a flexible steelmaking process for efficient production of small batches of steel would be required. The strategic nature of process flexibility investments is discussed.