Primary ironmaking . 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: •
Blast furnaces — which made
pig iron (or sometimes finished
cast iron goods) from
iron ore; •
Bloomeries — where
bar iron was produced from
iron ore by direct reduction; •
Electrolytic smelting — Employs a
chromium/iron
anode that can survive a to produce decarbonized iron and 2/3 of a ton of industrial-quality oxygen per ton of iron. A thin film of metal oxide forms on the anode in the intense heat. The oxide forms a protective layer that prevents excess consumption of the base metal. •
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); •
Foundries — where
pig iron was remelted in an air furnace or in a foundry cupola to produce cast iron goods; •
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 and then to be drawn out into
bar iron in a
rolling mill.
Modern steelmaking , Finland 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. The mills operating converters of any type are better called steelworks, ironworks referring to former processes, like
puddling.
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==