Wrought iron in the context of "Water wheel"

Puddling is the process of converting pig iron to bar (wrought) iron in a coal fired reverberatory furnace. It was developed in England during the 1780s. The molten pig iron was stirred in a reverberatory furnace, in an oxidizing environment to burn the carbon, resulting in wrought iron. It was one of the most important processes for making the first appreciable volumes of valuable and useful bar iron (malleable wrought iron) without the use of charcoal. Eventually, the furnace would be used to make small quantities of specialty steels.

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 to take place in Great Britain, and shortly afterwards, in North America. That expansion constitutes the beginnings of the Industrial Revolution so far as the iron industry is concerned. Most 19th century applications of wrought iron, including the Eiffel Tower, bridges, and the original framework of the Statue of Liberty, used puddled iron.

Ferrous metallurgy is the metallurgy of iron and its alloys. The earliest surviving prehistoric iron artifacts, from the 4th millennium BC in Egypt, were made from meteoritic iron-nickel. It is not known when or where the smelting of iron from ores began, but by the end of the 2nd millennium BC iron was being produced from iron ores in the region from Greece to India, The use of wrought iron (worked iron) was known by the 1st millennium BC, and its spread defined the Iron Age. During the medieval period, smiths in Europe found a way of producing wrought iron from cast iron, in this context known as pig iron, using finery forges. All these processes required charcoal as fuel.

By the 4th century BC southern India had started exporting wootz steel, with a carbon content between pig iron and wrought iron, to ancient China, Africa, the Middle East, and Europe. Archaeological evidence of cast iron appears in 5th-century BC China. New methods of producing it by carburizing bars of iron in the cementation process were devised in the 17th century. During the Industrial Revolution, new methods of producing bar iron emerged, by substituting charcoal in favor of coke, and these were later applied to produce steel, ushering in a new era of greatly increased use of iron and steel that some contemporaries described as a new "Iron Age".

Wire rope is composed of as few as two solid, metal wires twisted into a helix that forms a composite rope, in a pattern known as laid rope. Larger diameter wire rope consists of multiple strands of such laid rope in a pattern known as cable laid. Manufactured using an industrial machine known as a strander, the wires are fed through a series of barrels and spun into their final composite orientation.

In stricter senses, the term wire rope refers to a diameter larger than 9.5 mm (3⁄8 in), with smaller gauges designated cable or cords. Initially wrought iron wires were used, but today steel is the main material used for wire ropes.

Many significant developments in the history of science and technology in China took place during the Han dynasty (202 BCE – 220 CE).

The Han period saw great innovations in metallurgy. Following the inventions of the blast furnace and cupola furnace during the Zhou dynasty (c. 1046 – 256 BCE) to make pig iron and cast iron respectively, the Han period saw the development of steel and wrought iron by use of the finery forge and puddling process. With the drilling of deep boreholes into the earth, the Chinese used not only derricks to lift brine up to the surface to be boiled into salt, but also set up bamboo-crafted pipeline transport systems which brought natural gas as fuel to the furnaces.

A finery forge is a forge used to produce wrought iron from pig iron by decarburization in a process called "fining" which involved liquifying cast iron in a fining hearth and removing carbon from the molten cast iron through oxidation. Finery forges were used as early as the 3rd century BC in China. The finery forge process was replaced by the puddling process and the roller mill, both developed by Henry Cort in 1783–4, but not becoming widespread until after 1800.

A bloomery is a type of metallurgical furnace once used widely for smelting iron from its oxides. The bloomery was the earliest form of smelter capable of smelting iron. Bloomeries produce a porous mass of iron and slag called a bloom. The mix of slag and iron in the bloom, termed sponge iron, is usually consolidated and further forged into wrought iron. Blast furnaces, which produce pig iron, have largely superseded bloomeries.