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The Bessemer process was the first inexpensive industrial process for the mass-production of steel from a molten pig iron. The process is named after its inventor, Henry Bessemer, who took out a patent on the process in 1855. The process was independently discovered in 1851 by William Kelly.^[1][2] The process had also been used outside of Europe for hundreds of years, but not on an industrial scale.^[3] The key principle is removal of impurities from the iron by oxidation through air being blown through the molten iron. The oxidation also raises the temperature of the iron mass and keeps it molten. Image File history File links No higher resolution available. ... Industrial processes are procedures involving chemical or mechanical steps to aid in the manufacture of an item or items, usually carried out on a very large scale. ... For other uses, see Steel (disambiguation). ... Two weights used in the theatre and made of pig iron; because of this, they are dubbed pig weights or simply pigs. ... Henry Bessemer (1813-1898) Sir Henry Bessemer (January 19, 1813 – March 15, 1898), English engineer and inventor, was born at Charlton near Hitchin in Hertfordshire. ... Year 1855 (MDCCCLV) was a common year starting on Monday (link will display the full calendar) of the Gregorian Calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... William Kelly (August 22, 1811 - February 11, 1888), born in Pittsburgh, Pennsylvania, was an American inventor. ... Steelmaking is the second step in producing steel from iron ore. ... For other uses, see Iron (disambiguation). ... The most fundamental reactions in chemistry are the redox processes. ...

Bessemer converter, schematic diagram

Bessemer converter. ... Bessemer converter. ...

The details of the process

Bessemer Converter

The process is carried on in a large ovoid steel container lined with clay or dolomite called the Bessemer converter. The capacity of a converter was from 8 to 30 tons of molten iron with a usual charge being around 15 tons. At the top of the converter is an opening, usually tilted to the side relative to the body of the vessel, through which the iron is introduced and the finished product removed. The bottom is perforated with a number of channels called tuyères through which air is forced into the converter. The converter is pivoted on trunnions so that it can be rotated to receive the charge, turned upright during conversion, and then rotated again for pouring out the molten steel at the end. For other uses, see Clay (disambiguation). ... For other uses, see Dolomite (disambiguation). ... The trunnions are the protrusions from the side of the barrel that rest on the carriage A trunnion is a cylindrical protrusion used as a mounting point. ...

Oxidation

The oxidation process removes impurities such as silicon, manganese, and carbon as oxides. These oxides either escape as gas or form a , such as spiegeleisen (an iron-carbon-manganese alloy). Not to be confused with Silicone. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... For other uses, see Carbon (disambiguation). ... Spiegeleisen (German: Spiegel— mirror or specular; Eisen—iron) is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. ...

Managing the process

When the required steel had been formed, it was poured out into ladles and then transferred into moulds and the lighter slag is left behind. The conversion process (called the "blow") was completed in around twenty minutes. During this period the progress of the oxidation of the impurities was judged by the appearance of the flame issuing from the mouth of the converter: the modern use of photoelectric methods of recording the characteristics of the flame has greatly aided the blower in controlling the final quality of the product. After the blow, the liquid metal was recarburized to the desired point and other alloying materials are added, depending on the desired product.

Predecessor processes

Before the Bessemer process Britain had no practical method of reducing the carbon content of pig iron. Steel was manufactured by the reverse process of adding carbon to carbon-free wrought iron, usually imported from Sweden. The manufacturing process, called cementation process, consisted of heating bars of wrought iron together with charcoal for periods of up to a week in a long stone box. This produced blister steel. Up to 3 tons of expensive coke was burnt for each ton of steel produced. Such steel when rolled into bars was sold at £50 to £60 a long ton. The most difficult and work-intensive part of the process was however the production of wrought iron done in finery forges in Sweden. Decarburization is the process opposite to carburization, namely aimed at decreasing the content of carbon in metals (usually steel). ... Two weights used in the theatre and made of pig iron; because of this, they are dubbed pig weights or simply pigs. ... It has been suggested that Wrought iron furniture be merged into this article or section. ... The cementation process is a obsolete technique for making steel. ... Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. ... It has been suggested that this article or section be merged into crucible steel. ... Coke Coke is a solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal. ... Iron tapped from the blast furnace is pig iron, and contains significant amounts of carbon and silicon. ...

This process was refined in the 1700s with the introduction of Benjamin Huntsman's crucible steel making technique, which added an additional three hours firing time, and additional massive quantities of coke. In making crucible steel, the blister steel bars were broken into pieces and melted in small crucibles each containing 20 kg or so. This produced higher quality crucible steel, and increased the cost. The Bessemer process reduced to about ½ hour the time to make steel of this quality, while requiring only the coke needed initially to melt the pig iron. The earliest Bessemer converters produced steel for £7 a long ton, although they priced it initially at around £40 a ton. Events and trends The Bonneville Slide blocks the Columbia River near the site of present-day Cascade Locks, Oregon with a land bridge 200 feet (60 m) high. ... Benjamin Huntsman (1704 - 1776), English inventor and steel-manufacturer, was born in Lincolnshire. ... Crucible steel describes a number of different techniques for making steel alloy by slowly heating and cooling iron and carbon (typically in the form of charcoal) in a crucible. ... Crucible steel describes a number of different techniques for making steel alloy by slowly heating and cooling iron and carbon (typically in the form of charcoal) in a crucible. ... Two weights used in the theatre and made of pig iron; because of this, they are dubbed pig weights or simply pigs. ...

Bessemer converter, Kelham Island Museum, Sheffield, England (2002)

Bessemer Converter, Kelham Island Museum, Sheffield, England File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Bessemer Converter, Kelham Island Museum, Sheffield, England File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

History

Both Bessemer and Huntsman were based in the city of Sheffield, England. Sheffield has an international reputation for steel-making, which dates from 1740, when Benjamin Huntsman discovered the crucible technique for steel manufacture, at his workshop in the district of Handsworth. This process had an enormous impact on the quantity and quality of steel production and was only made obsolete, a century later, in 1856 by Henry Bessemer's invention of the Bessemer converter which allowed the true mass production of steel. Bessemer had moved his Bessemer Steel Company to Sheffield to be at the heart of the industry. The city's Kelham Island Museum still maintains one of the UK's last examples of a working Bessemer converter [from Workington, Cumbria] for public viewing. For other uses, see Sheffield (disambiguation). ... For other uses, see England (disambiguation). ... Steelmaking is the second step in producing steel from iron ore. ... Events May 31 - Friedrich II comes to power in Prussia upon the death of his father, Friedrich Wilhelm I. October 20 - Maria Theresia of Austria inherits the Habsburg hereditary dominions (Austria, Bohemia, Hungary and present-day Belgium). ... Handsworth is a suburb of south eastern Sheffield, in South Yorkshire, England. ... 1856 was a leap year starting on Tuesday (see link for calendar). ... The Kelham Island Industrial Museum occupies the site of a former steelworks on an island in the River Don in Sheffield, England. ...

Importance

The Bessemer process revolutionized steel manufacture by decreasing its cost, and greatly increasing the scale and speed, while also decreasing the labour requirements. Prior to its introduction, steel was far too expensive to make bridges or the for the framework for buildings and wrought iron had been used throughout the Industrial Revolution. After its introduction, steel and wrought iron became similarly priced, and most manufacturers turned to steel. It has been suggested that Wrought iron furniture be merged into this article or section. ... A Watt steam engine, the steam engine that propelled the Industrial Revolution in Britain and the world. ...

Obsolescence

In the U.S., commercial steel production using this method stopped in 1968. It was replaced by processes such as Linz-Donawitz process that offered better control of final chemistry. The Bessemer process was so fast (10-20 minutes for a heat) that it allowed little time for chemical analysis or adjustment of the alloying elements in the steel. Bessemer converters did not remove phosphorus efficiently from the molten steel; as low-phosporous ores became more expensive, conversion costs increased. The process only permitted a limited amount of scrap steel to be charged, further increasing costs, especially when scrap was inexpensive. Certain grades of steel were sensitive to the nitrogen which was part of the air blast passing through the steel. Basic oxygen steelmaking (BOS, Linz-Donawitz-Verfahren, LD-converter) is a method of converting molten iron to steel. ... General Name, symbol, number phosphorus, P, 15 Chemical series nonmetals Group, period, block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... A breakers yard in the UK, showing cars stacked on a metal grid to make it easier to find and remove usable parts. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ...

See also

• Henry Bessemer
• William Kelly
• Linz-Donawitz process
• Siemens-Martin process
• Basic oxygen steelmaking
• Sandvik
• 1862
• Ladle Analysis Formula

Henry Bessemer (1813-1898) Sir Henry Bessemer (January 19, 1813 – March 15, 1898), English engineer and inventor, was born at Charlton near Hitchin in Hertfordshire. ... William Kelly (August 22, 1811 - February 11, 1888), born in Pittsburgh, Pennsylvania, was an American inventor. ... Basic oxygen steelmaking (BOS, Linz-Donawitz-Verfahren, LD-converter) is a method of converting molten iron to steel. ... ... Basic oxygen steelmaking (BOS, Linz-Donawitz-Verfahren, LD-converter) is a method of converting molten iron to steel. ... Sandvik is a Swedish company founded in 1862 by Göran Fredrik Göransson at Sandviken. ... This article is about 1862 . ...

References

• A retrospective of 20th century steel making technology

External links

• Bessemer process

Notes

1. ^ "Bessemer process". Britannica 2. (2005). Encyclopedia Britannica. 168. Retrieved on 2005-08-06. 
2. ^ "Kelly, William". Britannica 6. (2005). Encyclopedia Britannica. 791. Retrieved on 2005-08-06. 
3. ^ Ponting, Clive (2000), World History, A New Perspective, Pimlico, ISBN 0-7126-6572-2