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Puddling was a process developed in England by Henry Cort during the period of 1783-84. The basic process involved a hearth and and oven. The pig iron was placed into the oven and heated. The metal was exposed to iron silicate and iron oxide, causing the iron oxide to combine with the carbon and rise to the surface. The "rabbler" would move the metal into lumps of iron weighing 200-300 pounds, commonly called "blooms". A second worker would run the blooms through a roller process to squeeze out excess iron silicate. The pressed blooms would then be run through a rolling mill to create muck bars. The muck bars were cut into short pieces, wired together, and placed in a coal-fired soak pit until they welded together. The welded set of muck bars were run through the rolling mill again and turned into a merchant bar of wrought iron.

Wrought iron is a commercial iron that has little use today and has been replaced by mild steel. It was commonly produced by the puddling process. The temperatures employed in its production are too low to render it fluid, it is heated until it forms a pasty mass then it is squeezed or forged. The process does not lend itself to removal of impurities so it contains an appreciable quantity of slag. It will not respond to any heat treatment designed to increase the hardness or strength.

The Bessemer process was developed as an extension of the puddling process. Pig iron from the blast furnace was melted and exposed to blasts of cold air. This removed the impurities from the iron and created steel.

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