Puddling Process

The puddling process is a method for converting brittle, carbon-rich pig iron into malleable wrought iron by melting it in a reverberatory furnace, where the metal is kept separate from the coal fuel and its flame, and stirring, or puddling, the molten iron by hand with a long rod so that the exposed metal reacts with the furnace's oxidizing atmosphere and burns off carbon. The English ironmaster Henry Cort patented the process in 1784, and it quickly replaced the older, more limited finery forge method as the principal way of producing wrought iron in Britain during the Industrial Revolution, since a single puddling furnace could process pig iron far faster and more consistently. Puddling remained the standard route to wrought iron through most of the nineteenth century, supplying the iron for early railways, bridges and ships, until the Bessemer and open hearth processes made cheap steel available and made wrought iron, and the puddling process that produced it, largely obsolete by the early twentieth century.