Continuous Casting

Every casting process before this one makes a discrete object: pour, freeze, break out, repeat. Steel was cast into ingots, and each ingot then had to be reheated, its shrunken and impure top cut off and scrapped, and the rest rolled down — an enormous expenditure of heat and metal to undo the shape casting had just created. Continuous casting abolishes the ingot. Molten steel is poured into a short water-cooled mould with no bottom; a solid shell forms against the walls; the strand is withdrawn steadily from below, still liquid inside, and is cooled and cut to length as it emerges. Siegfried Junghans developed the oscillating mould that made it work in the 1930s. It saves the reheating, saves the crop, and feeds the rolling mill directly.