Osmond iron (also spelt osmund and also called osborn) was wrought iron made by a particular process. This is associated with the first European production of cast iron in furnaces such as Lapphyttan in Sweden. [1]
Osmonds appear in some of the earliest English Customs accounts, for example in 1325. [2] The kappe was a Swedish weight used for osmond which occurs in a commercial treaty in Novgorod in 1203, and this implies the production of osmond iron. [3]
Osmond iron was made by melting pig iron in a hearth that is narrower and deeper than a typical finery in an English finery forge. The hearth had a charcoal fire blown with bellows through a tuyere. As the iron melted, the drops fell through the blast and congealed. They were then lifted with an iron bar into the blast. As they melted they were caught on the end of a large staff, held in the fire and turned rapidly so that the drops spread out, forming a ball. [4]
Osmonds reached England during the later Middle Ages through the port of Gdańsk. However, there were hammer mills in its hinterland and that of Lübeck, which made the osmonds into bar iron. In the 1620s, Gustav II Adolf of Sweden prohibited his subjects from exporting unfinished iron, and all trade in osmonds ceased. [5]
The osmond process was also used in the county of Mark in Westphalia, in southern Germany and Switzerland. [6]
The process was introduced to Wales in connection with the establishment by William Humfrey and others of wireworks at Tintern in 1566, an enterprise that was shortly afterwards taken over by the Company of Mineral and Battery Works. [7] Humfrey arranged to bring an expert maker of Osmond iron, Corslett Tinkhaus, from southwest Westphalia, where the production had reached a high level of technical proficiency. Tinkhaus arrived in Wales in 1567 and began working at Rhydygwern in the Glamorgan part of the lordship of Machen. This was where the first Machen Forge was, and he was evidently making osmond iron there. The iron was apparently forged with a tilt hammer, rather than the helve hammer, usual in finery forges. This was the raw material for the wireworks at Tintern. Osmond iron was made at Pontypool in the 18th century to supply wireworks there, and one of the forges there was still called the 'Osborn Forge' in the 19th century. [8]
Pig iron, also known as crude iron, is an intermediate good used by the iron industry in the production of steel. It is developed by smelting iron ore in a blast furnace. Pig iron has a high carbon content, typically 3.8–4.7%, along with silica and other dross, which makes it brittle and not useful directly as a material except for limited applications.
Wrought iron is an iron alloy with a very low carbon content in contrast to that of cast iron. It is a semi-fused mass of iron with fibrous slag inclusions, which give it a wood-like "grain" that is visible when it is etched, rusted, or bent to failure. Wrought iron is tough, malleable, ductile, corrosion resistant, and easily forge welded, but is more difficult to weld electrically.
Steelmaking is the process of producing steel from iron ore and/or scrap. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon are removed from the sourced iron, and alloying elements such as manganese, nickel, chromium, carbon and vanadium are added to produce different grades of steel.
A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. Blast refers to the combustion air being supplied above atmospheric pressure.
The Wealden iron industry was located in the Weald of south-eastern England. It was formerly an important industry, producing a large proportion of the bar iron made in England in the 16th century and most British cannon until about 1770. Ironmaking in the Weald used ironstone from various clay beds, and was fuelled by charcoal made from trees in the heavily wooded landscape. The industry in the Weald declined when ironmaking began to be fuelled by coke made from coal, which does not occur accessibly in the area.
An open-hearth furnace or open hearth furnace is any of several kinds of industrial furnace in which excess carbon and other impurities are burnt out of pig iron to produce steel. Because steel is difficult to manufacture owing to its high melting point, normal fuels and furnaces were insufficient for mass production of steel, and the open-hearth type of furnace was one of several technologies developed in the nineteenth century to overcome this difficulty. Compared with the Bessemer process, which it displaced, its main advantages were that it did not expose the steel to excessive nitrogen, was easier to control, and permitted the melting and refining of large amounts of scrap iron and steel.
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.
An ironworks or iron works is an industrial plant where iron is smelted and where heavy iron and steel products are made. The term is both singular and plural, i.e. the singular of ironworks is ironworks.
The Iron Act, also called the Importation, etc. Act 1749, was an Act of the Parliament of Great Britain, which was one of the legislative measures introduced within the system of Trade and Navigation Acts. The Act sought to increase the importation of pig and bar iron from its American colonies and to prevent the building of iron-related production facilities within these colonies, particularly in North America where these raw materials were identified. The dual purpose of the Act was to increase manufacturing capacity within Great Britain itself, and to limit potential competition from the colonies possessing the raw materials.
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 without the use of charcoal. Eventually, the furnace would be used to make small quantities of specialty steels.
A tuyere or tuyère is a tube, nozzle or pipe allowing the blowing of air into a furnace or hearth.
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.
The Company of Mineral and Battery Works was, with the Society of the Mines Royal, one of two mining monopolies created by Elizabeth I. The Company's rights were based on a patent granted to William Humfrey on 17 September 1565. This was replaced on 28 May 1568 by a patent of incorporation, making it an early joint stock company. The Society of the Mines Royal was incorporated on the same day.
Lapphyttan or Lapphyttejarn in Norberg Municipality, Sweden, may be regarded as the type site for the Medieval Blast Furnace. Its date is probably between 1150 and 1350. It produced cast iron, which was then fined to make ferritic wrought iron cake or bun-like blooms. These were then cut into lumps for trade. It is thought that they correspond to the iron pieces known as osmonds. Osmonds occur in English Customs records in the 1250s and seem to be alluded to in a commercial treaty with Novgorod in 1203. Lapphyttan is a part of Ecomuseum Bergslagen.
A Walloon forge is a type of finery forge that decarbonizes pig iron into wrought 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 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.
Cornwall Iron Furnace is a designated National Historic Landmark that is administered by the Pennsylvania Historical and Museum Commission in Cornwall, Lebanon County, Pennsylvania in the United States. The furnace was a leading Pennsylvania iron producer from 1742 until it was shut down in 1883. The furnaces, support buildings and surrounding community have been preserved as a historical site and museum, providing a glimpse into Lebanon County's industrial past. The site is the only intact charcoal-burning iron blast furnace in its original plantation in the western hemisphere. Established by Peter Grubb in 1742, Cornwall Furnace was operated during the Revolution by his sons Curtis and Peter Jr. who were major arms providers to George Washington. Robert Coleman acquired Cornwall Furnace after the Revolution and became Pennsylvania's first millionaire. Ownership of the furnace and its surroundings was transferred to the Commonwealth of Pennsylvania in 1932.
Coslett is an uncommon surname with origins in 16th-century Wales. Main spelling variants are Cosslett and Coslet, though Corslet, Coslette and other spellings have been recorded.
The Lancashire hearth was used to fine pig iron, removing carbon to produce wrought iron.
A metallurgical furnace, often simply referred to as a furnace when the context is known, is an industrial furnace used to heat, melt, or otherwise process metals. Furnaces have been a central piece of equipment throughout the history of metallurgy; processing metals with heat is even its own engineering specialty known as pyrometallurgy.