What a 4-percent yield gain is worth in an electric-arc furnace

Yield gains in a melt shop are usually quoted as percentages and rarely priced. On three recent programs we traced every lost tonne to a cause — furnace practice on alloy changes, dross handling, and a maintenance calendar that kept slipping — then valued each at the month's actual selling price. The numbers concentrated fast: two causes carried three-quarters of the loss.

A four-point yield gain on a 600,000-tonne shop is roughly the margin of a mid-sized product line. That is why we work the constraint first and leave the forty-initiative list alone.