The Bessemer process was the first inexpensive industrial process 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. Industrial processes are the key components of heavy industry for the mass-production of steel Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten. Carbon and other elements act as a hardening agent, preventing from molten pig iron Pig iron is the intermediate product of smelting iron ore with coke, usually with limestone as a flux. Pig iron has a very high carbon content, typically 3.5–4.5%, which makes it very brittle and not useful directly as a material except for limited applications. The process is named after its inventor, Henry Bessemer Sir Henry Bessemer was an English engineer and inventor. Bessemer's name is chiefly known in connection with the Bessemer process for the manufacture of steel, who took out a patent on the process in 1855. The process was independently discovered in 1851 by William Kelly William Kelly , born in Pittsburgh, Pennsylvania, was an American inventor. Kelly studied metallurgy at the Western University of Pennsylvania. Instead of getting a job as a scientist, Kelly, his brother, and his brother-in-law started a dry goods and commission business, which they called McShane & Kelly. After a fire destroyed their.^[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 Steelmaking is the second step in producing steel from iron ore. In this stage, impurities such as sulfur, phosphorus, and excess carbon are removed from the raw iron, and alloying elements such as manganese, nickel, chromium and vanadium are added to produce the exact steel required from the iron Iron is the most common element in the earth as a whole, and the fourth most common in the Earth's crust. It is produced as a result of stellar fusion in high-mass stars, and it is the heaviest stable element produced by stellar fusion because the fusion of iron is the last nuclear fusion reaction that is exothermic. Iron is the most widely used by oxidation Redox describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. This can be either a simple redox process, such as the oxidation of carbon to yield carbon dioxide (CO2) or the reduction of carbon by hydrogen to yield methane (CH4), or a complex process such as the oxidation of sugar(C6H12O6) in the with air being blown through the molten iron. The oxidation also raises the temperature of the iron mass and keeps it molten.

Details

Bessemer converter

The process is carried on in a large ovoid steel container lined with clay Clay is a naturally occurring material composed primarily of fine-grained minerals. Clay deposits are mostly composed of clay minerals, a subtype of phyllosilicate minerals, which impart plasticity and harden when fired or dried; they also may contain variable amounts of water trapped in the mineral structure by polar attraction. Organic materials or dolomite Dolomite is the name of a sedimentary carbonate rock and a mineral, both composed of calcium magnesium carbonate Ca 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 The term is also used to describe the wheel that a rotating cylinder runs on. For example, a lapidiary cylinder runs on a pair of rollers, similar to trunnions. The sugar industry uses rotating cylinders up to 6.7 meters in diameter and 40 meters long weighing around 1000 tonnes. These rotate at around 30 revolutions per hour. They are supported 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.

Oxidation

The oxidation process removes impurities such as silicon Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. It is the eighth most common element in the universe by mass, but silicon very rarely occurs as the pure free element in nature. Silicon is more widely, manganese Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature (often in combination with iron), and in many minerals. As a free element, manganese is a metal with important industrial metal alloy uses, particularly in stainless steels, and carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of as oxides. These oxides either escape as gas or form a solid slag. The refractory lining of the converter also plays a role in the conversion—the clay lining is used in the acid An acid is any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity greater than in pure water, i.e. a pH less than 7.0 in its standard state. That approximates the modern definition of Johannes Nicolaus Brønsted and Martin Lowry, who independently defined an acid as a compound which donates a hydrogen Bessemer, in which there is low phosphorus Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate rocks. Elemental phosphorus exists in two major forms – white phosphorus and red phosphorus. Although the term "phosphorescence", meaning glow after in the raw material. Dolomite is used when the phosphorus content is high in the basic In chemistry, a base is most commonly thought of as an aqueous substance that can accept hydrogen ions. Bases are also the oxides or hydroxides of metals. A soluble base is also often referred to as an alkali if hydroxide ions are involved. This refers to the Brønsted-Lowry theory of acids and bases. Alternative definitions of bases include Bessemer (limestone Limestone is a sedimentary rock composed largely of the mineral calcite . Like most other sedimentary rocks, limestones are composed of grains; however, most grains in limestone grains are skeletal fragments of marine organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts, and or magnesite Magnesite occurs as veins in and an alteration product of ultramafic rocks, serpentinite and other magnesium rich rock types in both contact and regional metamorphic terranes. These magnesites often are cryptocrystalline and contain silica as opal or chert linings are also sometimes used instead of dolomite)—this is also known as a Gilchrist-Thomas converter, named after its inventor, Sidney Gilchrist Thomas Sidney Gilchrist Thomas was an English inventor. Thomas was born at Canonbury, London and was educated at Dulwich College. . His father, a Welshman, was in the civil service, and his mother was the daughter of the Rev. James Gilchrist. His father's death left his family with a considerably reduced income, he gave up his original idea of becoming a. In order to give the steel the desired properties, other substances could be added to the molten steel when conversion was complete, such as spiegeleisen Spiegeleisen is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. Historically, this was the standard form in which manganese was traded and used in steel making (see Bessemer process); today, manganese is usually traded and used in more concentrated form, 80% manganese content being typical (an iron-carbon-manganese alloy).

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 The United Kingdom of Great Britain and Ireland was the formal name of the United Kingdom from 1 January 1801 until 12 April 1927. It was formed by the merger of the Kingdom of Great Britain and the Kingdom of Ireland, with Ireland being governed directly from Westminster through its Dublin Castle administration had no practical method of reducing the carbon content Decarburization is the process opposite to carburization, namely aimed at decreasing the content of carbon in metals of pig iron Pig iron is the intermediate product of smelting iron ore with coke, usually with limestone as a flux. Pig iron has a very high carbon content, typically 3.5–4.5%, which makes it very brittle and not useful directly as a material except for limited applications. Steel was manufactured by the reverse process of adding carbon to carbon-free wrought iron Wrought iron is an iron alloy with a very low carbon content, in comparison to steel, and has fibrous inclusions, known as slag. This is what gives it a "grain" resembling wood, which is visible when it is etched or bent to the point of failure. Wrought iron is tough, malleable, ductile and easily welded. Historically, it was known as &, usually imported from Sweden Sweden (pronounced /ˈswiːdən/ SWEE-dən, Swedish: Sverige [ˈsvær.jə]), officially the Kingdom of Sweden (Swedish: Konungariket Sverige (help·info)), is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden has land borders with Norway to the west and Finland to the northeast, and water borders with Denmark, Germany and. The manufacturing process, called cementation process The cementation process is an obsolete technique for making steel by carburization of iron. Unlike modern steelmaking it increased the amount of carbon in the iron. It was apparently developed before the 17th century. The only remaining example of an intact cementation furnace in Great Britain is the one on Doncaster Street in Sheffield, consisted of heating bars of wrought iron together with charcoal Charcoal is the dark grey residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood, sugar, bone char, or other substances in the absence of oxygen . The resulting soft, brittle, lightweight, black, porous for periods of up to a week in a long stone box. This produced blister steel The cementation process is an obsolete technique for making steel by carburization of iron. Unlike modern steelmaking it increased the amount of carbon in the iron. It was apparently developed before the 17th century. Up to 3 tons of expensive coke Coke is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal. Cokes from coal are grey, hard, and porous 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, however, was the production of wrought iron done in finery forges Iron tapped from the blast furnace is pig iron, and contains significant amounts of carbon and silicon. To produce malleable wrought iron, it needs to undergo a further process. In the early modern period, this was carried out in a finery forge in Sweden.

This process was refined in the 1700s with the introduction of Benjamin Huntsman Benjamin Huntsman was an English inventor and manufacturer of cast or crucible steel's crucible steel Crucible steel describes a number of different techniques for making steel in a crucible. Its manufacture is essentially a refining process which is dependent on preexisting furnace products. Crucible steel has aroused considerable interest for well over a thousand years and there is a very considerable literature on its nature and production-making technique, which added an additional three hours firing time and required additional large 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 but increased the cost. The Bessemer process reduced to about half an hour the time needed to make steel of this quality while requiring only the coke needed to melt the pig iron initially. The earliest Bessemer converters produced steel for £7 a long ton, although it initially sold for around £40 a ton.

History

Historian Robert Hartwell points out that the 11th century Chinese of the Song Dynasty The Song Dynasty was a ruling dynasty in China between 960 and 1279; it succeeded the Five Dynasties and Ten Kingdoms Period, and was followed by the Yuan Dynasty. It was the first government in world history to issue banknotes or paper money, and the first Chinese government to establish a permanent standing navy. This dynasty also saw the first innovated a "partial decarbonization" method of repeated forging of cast iron Cast iron usually refers to grey iron, but also identifies a large group of ferrous alloys, which solidify with a eutectic. The colour of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due to its carbide impurities which allow cracks to pass straight through. Grey cast iron is under a cold blast.^[4] The historians Joseph Needham and Wertime acknowledged that this was the predecessor to the Bessemer process of making steel. This process was first described by the prolific scholar and polymath government official Shen Kuo Shen Kuo or Shen Gua (1031–1095), style name Cunzhong (存中) and pseudonym Mengqi (now usually given as Mengxi) Weng (夢溪翁), was a polymathic Chinese scientist and statesman of the Song Dynasty (960–1279). Excelling in many fields of study and statecraft, he was a mathematician, astronomer, meteorologist, geologist, zoologist, botanist, (1031–1095) in 1075 when he visited Cizhou.^[4] Hartwell states that perhaps the earliest center where this was practiced was the great iron-production district along the Henan Henan , is a province of the People's Republic of China, located in the eastern central part of the country. Its one-character abbreviation is 豫 (pinyin: yù), named after Yuzhou Province (豫州 Yù Zhōu), a Han Dynasty province (zhou) that included parts of Henan. The name Henan means "south of the (Yellow) River" (Huang He)-Hebei Hebei (Chinese: 河北; pinyin: Héběi; Wade-Giles: Ho-pei; Postal map spelling: Hopeh) is a province of the People's Republic of China in the North China region. Its one-character abbreviation is "冀" (pinyin: jì), named after Ji Province, a Han Dynasty province (zhou) that included what is now southern Hebei. The name Hebei means & border during the 11th century.^[4]

In 1740 Benjamin Huntsman developed the crucible technique for steel manufacture, at his workshop in the district of Handsworth Handsworth is a suburb of south eastern Sheffield, in South Yorkshire, England. Handsworth has a population of approximately 15,000. It covers an overall area of approximately 5 square miles . It has five schools, four churches, a variety of small shops, a large supermarket (whose former incarnation on a different site was featured in The Full in Sheffield Sheffield (pronounced /ˈʃɛfiːld/ ) is a city and metropolitan borough of South Yorkshire, England. Its name derives from the River Sheaf, which runs through the city. Historically a part of the West Riding of Yorkshire, the city has grown from its largely industrial roots to encompass a wider economic base. The population of the City of. This process had an enormous impact on the quantity and quality of steel production.

Sir Henry Bessemer described the origin of his invention in Chapters 10 and 11 of his autobiography. According to this book at the time of the outbreak of the Crimean War The Crimean War was fought between the Russian Empire on one side and an alliance of the French Empire, the British Empire, the Ottoman Empire, the Kingdom of Sardinia, and the Duchy of Nassau on the other. The war was part of a long-running contest between the major European powers for influence over territories of the declining Ottoman Empire many English industrialists and inventors became interested in military technology and Bessemer himself developed a method for grooving artillery projectiles so that they could spin without the use of rifling Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy in the bore of the gun. He patented this method in 1854 and began developing it in conjunction with the government of France. After a successful day of testing of his method at the Polygon in France he had a conversation with Claude-Etienne Minié who stated that a key barrier to the use of the larger, heavier spinning projectiles would be the strength of the gun and in particular "...he [Minié] did not consider it safe in practice to fire a 30-lb. shot from a 12-pounder cast-iron gun. The real question, he said, was; Could any guns be made to stand such heavy projectiles?". This is what started Bessemer thinking about steel. At the time steel was difficult and expensive to make and was consequently used in only small items like cutlery and tools. Starting in January 1855 he began working on a way to produce steel in the massive quantities required for artillery Originally applied to any group of infantry primarily armed with mechanical projectile weapons,artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons. These engines comprise specialised devices which use some form of stored and by October he filed his first patent related to the Bessemer process.

According to his autobiography An autobiography is a book about the life of a person, written by that person Bessemer first started working with an ordinary reverbatory furnace A reverberatory furnace is a metallurgical or process furnace that isolates the material being processed from contact with the fuel, but not from contact with combustion gases. The term reverberation is used here in a generic sense of rebounding or reflecting, not in the acoustic sense of echoing but during a test a couple of pig ingots got off to the side of ladle and were sitting above it in the hot air of the furnace. When Bessemer went to push them into the ladle he found that they were steel shells: the hot air alone had converted the outer parts of the ingots to steel. This crucial discovery led him to completely redesign his furnace so that it would force high-pressure air through the molten iron using special air pumps. Intuitively this would seem to be folly because it would cool the iron, but due to exothermic oxidation both the silicon and carbon react with the excess oxygen leaving the surrounding molten iron even hotter, facilitating the conversion to steel.

Bessemer licenced the patent for his process to five ironmasters, for a total of £27,000, but the licences failed to produce the quality of steel he had promised and he later bought them back for £32,500^[5]. He realised the problem was due to impurities in the iron and concluded that the solution lay in knowing when to turn off the flow of air in his process; so that the impurities had been burnt off, but just the right amount of carbon remained. However, despite spending tens of thousands of pounds on experiments, he could not find the answer.^[6] Certain grades of steel are sensitive to the 78% nitrogen Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere which was part of the air blast passing through the steel.

The simple, but elegant, solution was first discovered by English metallurgist Robert Forester Mushet Robert Forester Mushet , an English metallurgist, born April 8, 1811, in Coleford, Gloucestershire. The youngest son of Agnes Wilson and David Mushet, an ironmaster, formerly of the Clyde, Alfreton and Whitclift Ironworks. In 1819 David Mushet built a foundry at Darkhill, in the Forest of Dean. Robert spent his formative years studying metallurgy, who had carried out thousands of scientifically valid experiments in the Forest of Dean The Forest of Dean is a geographical, historical and cultural region in the western part of the county of Gloucestershire, England. The forest is a roughly triangular plateau bounded by the River Wye to the west and north, the River Severn to the south, and the City of Gloucester to the east. His method was to first burn off, as far as possible, all the impurities and carbon, then reintroduce carbon and manganese by adding an exact amount of spiegeleisen. This had the effect of improving the quality of the finished product, increasing its malleability - its ability to withstand rolling and forging at high temperatures and making it more suitable for a vast array of uses.^[7][8][9]

The Dowlais Iron Company was the first licensee of the Bessemer process, constructing the world’s most powerful rolling mill in 1857, and producing its first Bessemer steel in 1865^[10].

The first Bessemer steel mill in the United States was established in 1855 in Wyandotte, Michigan, on the Detroit River, about 14 miles south of Detroit. Detroit became an early steel producing city in North America due to easy access to Great Lakes shipping and iron ore from northern Michigan, Wisconsin and Minnesota. These were major factors in development of Detroit as a renowned center of automobile manufacture.

Importance

The Bessemer process revolutionized steel manufacture by decreasing its cost, from £40 per long ton to £6-7 per long ton during its introduction, along with greatly increasing the scale and speed of production of this vital raw material. The process also decreased the labor requirements for steel-making. Prior to its introduction, steel was far too expensive to make bridges or the framework for buildings and thus wrought iron had been used throughout the Industrial Revolution. After the introduction of the Bessemer process, steel and wrought iron became similarly priced, and most manufacturers turned to steel. The availability of cheap steel allowed large bridges to be built and enabled the construction of railroads, skyscrapers, and large ships.^[11] Other important steel products—also made using the open hearth process—were steel cable, steel rod and sheet steel which enabled large, high-pressure boilers and high-tensile strength steel for machinery which enabled much more powerful engines, gears and axles than were possible previously. With large amounts of steel it became possible to build much more powerful guns and carriages, tanks, armored fighting vehicles and naval ships. Industrial steel also made possible the building of giant turbines and generators thus making the harnessing of water and steam power possible. The introduction of the large scale steel production process perfected by the Englishman Henry Bessemer paved the way to mass industrialisation as observed in the 19th-20th centuries.

Obsolescence

In the U.S., commercial steel production using this method stopped in 1968. It was replaced by processes such as the basic oxygen (Linz-Donawitz) process, which 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-phosphorus ores became more expensive, conversion costs increased. The process permitted only limited amount of scrap steel to be charged, further increasing costs, especially when scrap was inexpensive. Use of electric arc furnace technology competed favourably with the Bessemer process resulting in its obsolescence.

See also

• Open hearth furnace, the Siemens-Martin process
• Basic oxygen steelmaking, the Linz-Donawitz process

References

1. ^ "Bessemer process". Britannica. 2. Encyclopedia Britannica. 2005. pp. 168.
2. ^ "Kelly, William". Britannica. 6. Encyclopedia Britannica. 2005. pp. 791.
3. ^ Ponting, Clive (2000), World History, A New Perspective, Pimlico, ISBN 0-7126-6572-2
4. ^ ^{a b c} Hartwell, Robert (1966-03). "Markets, Technology, and the Structure of Enterprise in the Development of the Eleventh-Century Chinese Iron and Steel Industry". The Journal of Economic History 26 (1): 29–58. ISSN 00220507. http://www.jstor.org/stable/2116001. Retrieved 2009-11-24. Page 54.
5. ^ Bessemer, Sir Henry (1905). Sir Henry Bessemer, F.R.S.. Offices of "Engineering,". p172.
6. ^ Anstis 1997, p. 147.
7. ^ "Mushet, Robert Forester". Dictionary of National Biography, 1885–1900​. London: Smith, Elder & Co.
8. ^ http://www.fweb.org.uk/Dean/towns/colefordproject/people/mushet.html
9. ^ Anstis 1997, p. 140.
10. ^ Franks, Julian, Mayer, Colin & Rossi, Stefano: The Origination and Evolution of Ownership and Control, London Business School, December 2002, p.19[1]
11. ^ Misa, Thomas J. (1998-09-08). A Nation of Steel: The Making of Modern America, 1865-1925. The Johns Hopkins University Press. ISBN 0801860520. chapter 1 online

Bibliography

• Anstis, Ralph (1997), Man of Iron, Man of Steel: Lives of David and Robert Mushet, Albion House, ISBN 095113714X

External links

• The Engineer, 15 August 1856. Bessemer's explanation of his process.
• How the Modern Steel Furnace Does Its Work, Popular Science monthly, February 1919, page 30-31, Scanned by Google Books: http://books.google.com/books?id=7igDAAAAMBAJ&pg=PA30
• A retrospective of 20th century steel making technology

Categories: English inventions | Steelmaking

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• Henry Bessemer: Encyclopedia
• Bessemer Process: Encyclopedia

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