puddling (metallurgy)

Puddling was one step in one of the most important processes of making the first appreciable volumes of high-grade bar iron (malleable wrought iron) during the Industrial Revolution. In the original puddling technique, molten iron in a reverberatory furnace was stirred with rods, which were consumed in the process. It was one of the first processes for making bar iron without charcoal in Europe, although much earlier coal-based processes had existed in China. Eventually, the furnace would be used to make small quantities of specialty steels.