ironworks

Aerial view of Třinec Iron and Steel Works

Coat of arms of Eisenhüttenstadt ("city of ironworks"), Germany.

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An ironworks or iron works is a building or site where iron is smelted and where heavy iron and/or steel products are made. The term is both singular and plural, i.e. the plural of ironworks is ironworks.

An integrated ironworks in the 19th century usually included one or more blast furnaces and a number of puddling furnaces and/or a foundry with or without other kinds of ironworks.

The processes carried at ironworks are usually described as ferrous metallurgy, but the term siderurgy is also occasionally used. This is derived from the Greek words sideros - iron and ergon or ergos - work. This is an unusual term in English, and it is best regarded as an anglicisation of a term used in French, Spanish, and other Romance languages.

Varieties of ironworks

Primary ironmaking

Blast furnaces of Třinec Iron and Steel Works

Worker in a Foundry

Ironworks is used as an omnibus term covering works undertaking one or more iron-producing processes. Such processes or species of ironworks where they were undertaken include the following (the detailed articles on each process should be consulted) or alternatively the History of Ferrous Metallurgy:

• bloomeries - where bar iron was produced from iron ore by direct reduction;
• Blast furnaces - which made pig iron (or sometimes finished cast iron goods) from iron ore;
• foundries - where pig iron was remelted in an air furnace or in a foundry cupola to produce cast iron goods;
• finery forges - which fined pig iron to produce bar iron, using charcoal as fuel in a finery (hearth) and coal or charcoal in a chafery (hearth);
• potting and stamping forges with melting fineries using the first process in which bar iron was made from pig iron with mineral coal or coke, without the use of charcoal;
• puddling furnaces - a later process for the same purpose, again with coke as fuel. It was usually necessary for there to be a preliminary refining process in a coke refinery (also called running out furnace). After puddling, the puddled ball needed shingling (metallurgy) and then to be drawn out into bar iron in a rolling mills.

Modern steelmaking

From the 1850s, pig iron might be partly decarburised to produce mild steel using one of the following:

• The Bessemer process in a Bessemer converter, improved by the Gilchrist-Thomas process;
• The Siemens-Martin process in an Open hearth furnace;
• Electric arc furnace, introduced in 1907;
• Basic oxygen steelmaking, introduced in 1952.

For this period see History of the modern steel industry and Steelmaking.

Further processing

After bar iron had been produced in a finery forge or in the forge train of a rolling mill, it might undergo further processes in one of the following:

• A slitting mill - which cut a flat bar into rod iron suitable for making into nails.
• A tinplate works - where rolling mills made sheets of iron (later of steel), which were coated with tin.
• A plating forge with a tilt hammer, a lighter hammer with a rapid stroke rate, enabling the production of thinner iron, suitable for the manufacture of knives, other cutlery, and so on.
• A cementation furnace might be used to convert the bar iron (if it was pure enough) into blister steel by the cementation process, either as an end in itself or as the raw material for crucible steel.

Manufacture

Most of these processes did not produce finished goods. Further processes were often manual, including

• Manufacturing by blacksmiths or more specialist kind of smith.
• It might be used in shipbuilding.

In the context of the iron industry, the term manufacture is best reserved for this final stage.

Notable ironworks

Great Britain

• Coalbrookdale Ironworks
• Blaenavon Ironworks Heritage Site. Blaenavon (Blaenafon) South Wales
• Cyfarthfa Ironworks at Merthyr Tydfil, Glamorgan, south Wales
• Dowlais Ironworks also at Merthyr Tydfil
• Thames Ironworks and Shipbuilding Co. Ltd, a shipbuilding firm on the banks of the River Thames, England
• Iron town of Scunthorpe

United States of America

• Bath Iron Works in Maine
• Burden Iron Works in Troy, New York
• Cambria Iron Company in Johnstown, Pennsylvania
• Tredegar Iron Works at Richmond, Virginia
• Saugus Iron Works in Saugus, Massachusetts

Czech Republic

• Třinec Iron and Steel Works in Třinec, Czech Republic

Germany

• Völklingen Ironworks Heritage Site

Spain

• Altos Hornos de Vizcaya in Bilbao
• Arcelor facilities in Avilés and Gijón, formely Ensidesa.

Historical

• Kindiba, in Burkina Faso. Ancient iron extraction site consisting of mines and three clay built furnaces.
• Darkhill, in the Forest of Dean, England. Experimental ironworks established in 1819 and designated an 'Industrial Archaeological Site of International Importance'