Puddling (metallurgy)

Puddling (metallurgy)

Puddling was one step in one of the most important processes of making iron and steel 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.

Though it was not the first process to produce bar iron without charcoal, puddling was by far the most successful, and replaced the earlier potting and stamping processes, as well as the much older charcoal finery and bloomery processes. This enabled a great expansion of iron production in Great Britain to take place. That expansion constitutes the Industrial Revolution so far as the iron industry is concerned. Most 19th century applications of wrought iron, including the Eiffel Tower and the original framework of the Statue of Liberty used puddled iron.

Later, it was also used to produce a good-quality carbon steel; this was a highly skilled art, but both high-carbon and low-carbon steels were successfully produced on a small scale, particularly for swords, knives and other weapons.