![Bessemer converter](https://upload.wikimedia.org/wikipedia/commons/6/61/Bessemer_converter.jpg)
The Bessemer process was the first inexpensive
industrial process
Industrial processes are procedures involving chemical, physical, electrical or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy ind ...
for the
mass production
Mass production, also known as flow production or continuous production, is the production of substantial amounts of standardized products in a constant flow, including and especially on assembly lines. Together with job production and batch ...
of
steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...
from molten
pig iron
Pig iron, also known as crude iron, is an intermediate product of the iron industry in the production of steel which is obtained by smelting iron ore in a blast furnace. Pig iron has a high carbon content, typically 3.8–4.7%, along with silic ...
before the development of the
open hearth furnace
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 melt ...
. The key principle is
removal of impurities from the
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
by
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
with air being blown through the molten iron. The oxidation also raises the temperature of the iron mass and keeps it molten.
Related
decarburizing
Decarburization (or decarbonization) is the process of decreasing carbon content, which is the opposite of carburization.
The term is typically used in metallurgy, describing the decrease of the content of carbon in metals (usually steel). Decar ...
with air processes had been used outside Europe for hundreds of years, but not on an industrial scale. One such process (similar to
puddling) was known in the 11th century in East Asia, where the scholar
Shen Kuo
Shen Kuo (; 1031–1095) or Shen Gua, courtesy name Cunzhong (存中) and pseudonym Mengqi (now usually given as Mengxi) Weng (夢溪翁),Yao (2003), 544. was a Chinese polymathic scientist and statesman of the Song dynasty (960–1279). Shen wa ...
of that era described its use in the Chinese iron and steel industry.
In the 17th century, accounts by European travelers detailed its possible use by the Japanese.
The modern process is named after its inventor, the Englishman
Henry Bessemer
Sir Henry Bessemer (19 January 1813 – 15 March 1898) was an English inventor, whose steel-making process would become the most important technique for making steel in the nineteenth century for almost one hundred years from 1856 to 1950. He ...
, who took out a
patent
A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...
on the process in 1856.
The process was said to be independently discovered in 1851 by the American inventor
William Kelly though the claim is controversial.
The process using a basic
refractory
In materials science, a refractory material or refractory is a material that is resistant to decomposition by heat, pressure, or chemical attack, and retains strength and form at high temperatures. Refractories are polycrystalline, polyphase, ...
lining is known as the "basic Bessemer process" or
Gilchrist–Thomas process
The Gilchrist–Thomas process or Thomas process is a historical process for refining pig iron, derived from the Bessemer converter. It is named after its inventors who patented it in 1877: Percy Carlyle Gilchrist and his cousin Sidney Gilchr ...
after the English discoverers
Percy Gilchrist
Percy Carlyle Gilchrist FRS (27 December 1851 – 16 December 1935) was a British chemist and metallurgist.
Life
Gilchrist was born in Lyme Regis, Dorset, the son of Alexander and Anne Gilchrist and studied at Felsted and the Royal School of ...
and
Sidney Gilchrist Thomas
Sidney Gilchrist Thomas (16 April 1850 – 1 February 1885) was an English inventor, best known for his role in the iron and steel industry.
Life
Thomas was born at Canonbury, London, and was educated at Dulwich College. His father, a Welshman, w ...
.
History
Early history
A system akin to the Bessemer process has existed since the 11th century in East Asia.
Economic historian Robert Hartwell writes that the Chinese of the
Song Dynasty
The Song dynasty (; ; 960–1279) was an imperial dynasty of China that began in 960 and lasted until 1279. The dynasty was founded by Emperor Taizu of Song following his usurpation of the throne of the Later Zhou. The Song conquered the rest ...
(960–1279 CE) innovated a "partial decarbonization" method of repeated forging of
cast iron
Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impuriti ...
under a cold blast.
Sinologist
Sinology, or Chinese studies, is an academic discipline that focuses on the study of China primarily through Chinese philosophy, language, literature, culture and history and often refers to Western scholarship. Its origin "may be traced to the ex ...
Joseph Needham
Noel Joseph Terence Montgomery Needham (; 9 December 1900 – 24 March 1995) was a British biochemist, historian of science and sinologist known for his scientific research and writing on the history of Chinese science and technology, in ...
and historian of metallurgy Theodore A. Wertime have described the method as a 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 (; 1031–1095) or Shen Gua, courtesy name Cunzhong (存中) and pseudonym Mengqi (now usually given as Mengxi) Weng (夢溪翁),Yao (2003), 544. was a Chinese polymathic scientist and statesman of the Song dynasty (960–1279). Shen wa ...
(1031–1095) in 1075, when he visited Cizhou.
Hartwell states that perhaps the earliest center where this was practiced was the great iron-production district along the
Henan
Henan (; or ; ; alternatively Honan) is a landlocked province of China, in the central part of the country. Henan is often referred to as Zhongyuan or Zhongzhou (), which literally means "central plain" or "midland", although the name is al ...
–
Hebei
Hebei or , (; alternately Hopeh) is a northern province of China. Hebei is China's sixth most populous province, with over 75 million people. Shijiazhuang is the capital city. The province is 96% Han Chinese, 3% Manchu, 0.8% Hui, an ...
border during the 11th century.
In the 15th century, the
finery process, another process which shares the air-blowing principle with the Bessemer process, was developed in Europe. In 1740,
Benjamin Huntsman
Benjamin Huntsman (4 June 170420 June 1776) was an English inventor and manufacturer of cast or crucible steel.
Biography
Huntsman was born the fourth child of William and Mary (née Nainby) Huntsman, a Quaker farming couple, in Epworth, Li ...
developed the
crucible technique
Crucible steel is steel made by melting pig iron (cast iron), iron, and sometimes steel, often along with sand, glass, ashes, and other fluxes, in a crucible. In ancient times steel and iron were impossible to melt using charcoal or coal fires ...
for steel manufacture, at his workshop in the district of
Handsworth in
Sheffield
Sheffield is a city status in the United Kingdom, city in South Yorkshire, England, whose name derives from the River Sheaf which runs through it. The city serves as the administrative centre of the City of Sheffield. It is Historic counties o ...
. This process had an enormous impact on the quantity and quality of steel production, but it was unrelated to the Bessemer-type process employing decarburization.
![MandelsloJAC1228](https://upload.wikimedia.org/wikipedia/commons/9/9f/MandelsloJAC1228.JPG)
The Japanese may have made use of a Bessemer-type process, which was observed by European travellers in the 17th century.
The adventurer
Johan Albrecht de Mandelslo
Johan Albrecht de Mandelslo (1616–1644) was a seventeenth-century German adventurer, who wrote about his travels through Iran (Persia) and India. Born at Schönberg in Mecklenburg, Germany.Adam Olearius, ''The Voyages and Travels of the Ambassad ...
describes the process in a book published in English in 1669. He writes, "They have, among others, particular invention for the melting of iron, without the using of fire, casting it into a tun done about on the inside without about half a foot of earth, where they keep it with continual blowing, take it out by ladles full, to give it what form they please." According to historian Donald Wagner, Mandelslo did not personally visit Japan, so his description of the process is likely derived from accounts of other Europeans who had traveled to Japan. Wagner believes that the Japanese process may have been similar to the Bessemer process, but cautions that alternative explanations are also plausible.
Bessemer's patent
![William Kelly (inventor)](https://upload.wikimedia.org/wikipedia/commons/0/0c/William_Kelly_%28inventor%29.jpg)
In the early to mid-1850s, the American inventor
William Kelly experimented with a method similar to the Bessemer process. Wagner
writes that Kelly may have been inspired by techniques introduced by Chinese ironworkers hired by Kelly in 1854.
The claim that both Kelly and Bessemer invented the same process remains controversial. When Bessemer's patent for the process was reported by ''
Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...
'', Kelly responded by writing a letter to the magazine. In the letter, Kelly states that he had previously experimented with the process and claimed that Bessemer knew of Kelly's discovery. He wrote that "I have reason to believe my discovery was known in England three or four years ago, as a number of English puddlers visited this place to see my new process. Several of them have since returned to England and may have spoken of my invention there."
It is suggested Kelly's process was less developed and less successful than Bessemer's process.
Sir Henry Bessemer
Sir Henry Bessemer (19 January 1813 – 15 March 1898) was an English inventor, whose steel-making process would become the most important technique for making steel in the nineteenth century for almost one hundred years from 1856 to 1950. He ...
described the origin of his invention in his
autobiography
An autobiography, sometimes informally called an autobio, is a self-written account of one's own life.
It is a form of biography.
Definition
The word "autobiography" was first used deprecatingly by William Taylor in 1797 in the English peri ...
written in 1890. During the outbreak of the
Crimean War
The Crimean War, , was fought from October 1853 to February 1856 between Russia and an ultimately victorious alliance of the Ottoman Empire, France, the United Kingdom and Piedmont-Sardinia.
Geopolitical causes of the war included the de ...
, many English industrialists and inventors became interested in military technology. According to Bessemer, his invention was inspired by a conversation with
Napoleon III
Napoleon III (Charles Louis Napoléon Bonaparte; 20 April 18089 January 1873) was the first President of France (as Louis-Napoléon Bonaparte) from 1848 to 1852 and the last monarch of France as Emperor of the French from 1852 to 1870. A nephew ...
in 1854 pertaining to the steel required for better artillery. Bessemer claimed that it "was the spark which kindled one of the greatest revolutions that the present century had to record, for during my solitary ride in a cab that night from Vincennes to Paris, I made up my mind to try what I could to improve the quality of iron in the manufacture of guns."
At the time, steel was used to make only small items like cutlery and tools, but was too expensive for cannons. Starting in January 1855, he began working on a way to produce steel in the massive quantities required for
artillery
Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during siege ...
and by October he filed his first patent related to the Bessemer process. He patented the method a year later in 1856.
![Henry Bessemer (1813-1898)](https://upload.wikimedia.org/wikipedia/commons/8/8b/Henry_Bessemer_%281813-1898%29.jpg)
Bessemer licensed the patent for his process to four
ironmaster
An ironmaster is the manager, and usually owner, of a forge or blast furnace for the processing of iron. It is a term mainly associated with the period of the Industrial Revolution, especially in Great Britain.
The ironmaster was usually a large ...
s, for a total of £27,000, but the licensees failed to produce the quality of steel he had promised—it was "rotten hot and rotten cold", according to his friend,
William Clay—and he later bought them back for £32,500. His plan had been to offer the licenses to one company in each of several geographic areas, at a royalty price per ton that included a lower rate on a proportion of their output in order to encourage production, but not so large a proportion that they might decide to reduce their selling prices. By this method he hoped to cause the new process to gain in standing and market share.
He realised that the technical 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 were burned off but just the right amount of
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
remained. However, despite spending tens of thousands of pounds on experiments, he could not find the answer. Certain grades of steel are sensitive to the 78%
nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
which was part of the air blast passing through the steel.
The solution was first discovered by English metallurgist
Robert Forester Mushet
Robert Forester Mushet (8 April 1811 – 29 January 1891) was a British metallurgist and businessman, born on 8 April 1811, in Coleford, in the Forest of Dean, Gloucestershire, England. He was the youngest son of Scottish parents, Agnes Wilson ...
, who had carried out thousands of 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. It forms a roughly triangular plateau bounded by the River Wye to the west and northwest, Herefordshire to the n ...
. His method was to first burn off, as far as possible, ''all'' the impurities and carbon, then reintroduce carbon and
manganese
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
by adding an exact amount of
spiegeleisen
Spiegeleisen (literally "mirror-iron", —mirror or specular; —iron) is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. Spiegeleisen is sometimes also referred to as ''specular pig iron' ...
, an alloy of iron and manganese with trace amounts of carbon and
silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...
. This had the effect of improving the quality of the finished product, increasing its
malleability
Ductility is a List of materials properties, mechanical property commonly described as a material's amenability to Drawing (manufacturing), drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a materia ...
—its ability to withstand rolling and forging at high temperatures and making it more suitable for a vast array of uses. Mushet's patent ultimately lapsed due to Mushet's inability to pay the patent fees and was acquired by Bessemer. Bessemer earned over 5 million dollars in royalties from the patents.
The first company to license the process was the Manchester firm of
W & J Galloway, and they did so before Bessemer announced it at Cheltenham in 1856. They are not included in his list of the four to whom he refunded the license fees. However, they subsequently rescinded their license in 1858 in return for the opportunity to invest in a partnership with Bessemer and others. This partnership began to manufacture steel in Sheffield from 1858, initially using imported charcoal pig iron from
Sweden
Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...
. This was the first commercial production.
A 20% share in the Bessemer patent was also purchased for use in Sweden and Norway by Swedish trader and Consul
Göran Fredrik Göransson
Göran Fredrik Göransson (20 January 1819 – 12 May 1900) was a Sweden, Swedish merchant, ironmaster and industrialist. He was the founder of the company ''Sandvikens Jernverks AB'' (now called Sandvik AB) and was the first person to implement t ...
during a visit to London in 1857. During the first half of 1858, Göransson, together with a small group of engineers, experimented with the Bessemer process at Edsken near
Hofors
Hofors () is a locality and the seat of Hofors Municipality, Gävleborg County, Sweden with 6,681 inhabitants in 2010.
Districts
*Born
*Böle
*Bönhusberget
*Centrum
*Göklund
*Hammaren
*Lillån
*Muntebo
*Rönningen
*Silverdale ...
, Sweden before he finally succeeded. Later in 1858 he again met with Henry Bessemer in London, managed to convince him of his success with the process, and negotiated the right to sell his steel in England. Production continued in Edsken, but it was far too small for the industrial-scale production needed. In 1862 Göransson built a new factory for his Högbo Iron and Steel Works company on the shore of Lake Storsjön, where the town of
Sandviken
Sandviken is a locality and the seat of Sandviken Municipality in Gävleborg County, Sweden with 39,234 inhabitants in 2019. It is situated about 25 km west of Gävle and lies approximately 190 km north of Stockholm. The rail journey t ...
was founded. The company was renamed Sandviken's Ironworks, continued to grow and eventually became
Sandvik
Sandvik AB is a Swedish multinational engineering company specializing in metal cutting, digital and additive manufacturing, mining and construction, stainless and special steel alloys, and industrial heating. The company was founded in Sweden ...
in the 1970s.
Industrial revolution in the United States
Alexander Lyman Holley
Alexander Lyman Holley (Lakeville, Connecticut, July 20, 1832 – Brooklyn, New York, January 29, 1882) was an American mechanical engineer, inventor, and founding member of the American Society of Mechanical Engineers (ASME). He was consider ...
contributed significantly to the success of Bessemer steel in the United States. His ''
A Treatise on Ordnance and Armor
A, or a, is the first letter and the first vowel of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''a'' (pronounced ), plural ''aes' ...
'' is an important work on contemporary weapons manufacturing and steel-making practices. In 1862, he visited Bessemer's Sheffield works, and became interested in licensing the process for use in the US. Upon returning to the US, Holley met with two iron producers from
Troy, New York
Troy is a city in the U.S. state of New York and the county seat of Rensselaer County. The city is located on the western edge of Rensselaer County and on the eastern bank of the Hudson River. Troy has close ties to the nearby cities of Albany a ...
,
John F. Winslow
John Flack Winslow (November 10, 1810 – March 10, 1892) was an American businessman and iron manufacturer who was the fifth president of Rensselaer Polytechnic Institute.
Life
He was born on November 10, 1810, in Bennington, Vermont, and w ...
and
John Augustus Griswold
John Augustus Griswold (November 11, 1818 – October 31, 1872) was an American businessman and politician from New York. He served three terms in the U.S. House of Representatives from 1863 to 1869.
Early life
Griswold was born on November ...
, who asked him to return to the United Kingdom and negotiate with the
Bank of England
The Bank of England is the central bank of the United Kingdom and the model on which most modern central banks have been based. Established in 1694 to act as the English Government's banker, and still one of the bankers for the Government of ...
on their behalf. Holley secured a license for Griswold and Winslow to use Bessemer's patented processes and returned to the United States in late 1863.
The trio began setting up a mill in
Troy, New York
Troy is a city in the U.S. state of New York and the county seat of Rensselaer County. The city is located on the western edge of Rensselaer County and on the eastern bank of the Hudson River. Troy has close ties to the nearby cities of Albany a ...
in 1865. The factory contained a number of Holley's innovations that greatly improved productivity over Bessemer's factory in Sheffield, and the owners gave a successful public exhibition in 1867. The Troy factory attracted the attention of the
Pennsylvania Railroad
The Pennsylvania Railroad (reporting mark PRR), legal name The Pennsylvania Railroad Company also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. It was named ...
, which wanted to use the new process to manufacture steel rail. It funded Holley's second mill as part of its Pennsylvania Steel subsidiary. Between 1866 and 1877, the partners were able to license a total of 11 Bessemer steel mills.
One of the investors they attracted was
Andrew Carnegie
Andrew Carnegie (, ; November 25, 1835August 11, 1919) was a Scottish-American industrialist and philanthropist. Carnegie led the expansion of the American steel industry in the late 19th century and became one of the richest Americans i ...
, who saw great promise in the new steel technology after a visit to Bessemer in 1872, and saw it as a useful adjunct to his existing businesses, the
Keystone Bridge Company
Keystone or key-stone or ''variation'', may refer to:
* Keystone (architecture), a central stone or other piece at the apex of an arch or vault
* Keystone (cask), a fitting used in ale casks
Business
* Keystone Law, a full-service law firm
* D ...
and the Union Iron Works. Holley built the new steel mill for Carnegie, and continued to improve and refine the process. The new mill, known as the
Edgar Thomson Steel Works The Edgar Thomson Steel Works is a steel mill in the Pittsburgh area communities of Braddock and North Braddock, Pennsylvania, United States. It has been active since 1875. It is currently owned by U.S. Steel and is known as Mon Valley Works – E ...
, opened in 1875, and started the growth of the United States as a major world steel producer. Using the Bessemer process,
Carnegie Steel
Carnegie Steel Company was a steel-producing company primarily created by Andrew Carnegie and several close associates to manage businesses at steel mills in the Pittsburgh, Pennsylvania area in the late 19th century. The company was formed ...
was able to reduce the costs of steel
railroad
Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...
rails from $100 per ton to $50 per ton between 1873 and 1875. The price of steel continued to fall until Carnegie was selling rails for $18 per ton by the 1890s. Prior to the opening of Carnegie's Thomson Works, steel output in the United States totaled around 157,000 tons per year. By 1910, American companies were producing 26 million tons of steel annually.
William Walker Scranton
William Walker Scranton (April 4, 1844 – December 3, 1916) was an American businessman based in Scranton, Pennsylvania. He became president and manager of the Lackawanna Iron and Coal Company after his father's death in 1872. The company ...
, manager and owner of the
Lackawanna Iron & Coal Company in
Scranton, Pennsylvania
Scranton is a city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Lackawanna County, Pennsylvania, Lackawanna County. With a population of 76,328 as of the 2020 United States census, 2020 U ...
, had also investigated the process in Europe. He built a mill in 1876 using the Bessemer process for steel rails and quadrupled his production.
[Cheryl A. Kashuba, "William Walker led industry in the city"](_blank)
''The Times-Tribune,'' 11 July 2010, accessed 23 May 2016
Bessemer steel was used in the United States primarily for railroad rails. During the construction of the Brooklyn Bridge, a major dispute arose over whether
crucible steel
Crucible steel is steel made by melting pig iron (cast iron), iron, and sometimes steel, often along with sand, glass, ashes, and other flux (metallurgy), fluxes, in a crucible. In ancient times steel and iron were impossible to melt using char ...
should be used instead of the cheaper Bessemer steel. In 1877,
Abram Hewitt
Abram Stevens Hewitt (July 31, 1822January 18, 1903) was an American politician, educator, ironmaking industrialist, and lawyer who was mayor of New York City for two years from 1887–1888. He also twice served as a U.S. Congressman from an ...
wrote a letter urging against the use of Bessemer steel in the construction of the
Brooklyn Bridge
The Brooklyn Bridge is a hybrid cable-stayed/ suspension bridge in New York City, spanning the East River between the boroughs of Manhattan and Brooklyn. Opened on May 24, 1883, the Brooklyn Bridge was the first fixed crossing of the East River ...
. Bids had been submitted for both
crucible steel
Crucible steel is steel made by melting pig iron (cast iron), iron, and sometimes steel, often along with sand, glass, ashes, and other flux (metallurgy), fluxes, in a crucible. In ancient times steel and iron were impossible to melt using char ...
and Bessemer steel;
John A. Roebling's Sons
John is a common English name and surname:
* John (given name)
* John (surname)
John may also refer to:
New Testament
Works
* Gospel of John, a title often shortened to John
* First Epistle of John, often shortened to 1 John
* Second ...
submitted the lowest bid for Bessemer steel, but at Hewitt's direction, the contract was awarded to
J. Lloyd Haigh Co.
''J. The Jewish News of Northern California'', formerly known as ''Jweekly'', is a weekly print newspaper in Northern California, with its online edition updated daily. It is owned and operated by San Francisco Jewish Community Publications In ...
Technical details
![Bessemer Converter (PSF)](https://upload.wikimedia.org/wikipedia/commons/f/f1/Bessemer_Converter_%28PSF%29.jpg)
Using the Bessemer process, it took between 10 and 20 minutes to convert three to five tons of iron into steel — it would previously take at least a full day of heating, stirring and reheating to achieve this.
Oxidation
The blowing of air through the molten pig iron introduces oxygen into the melt which results in
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
, removing impurities found in the pig iron, such as
silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...
,
manganese
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
, and
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
in the form of
oxide
An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...
s. These oxides either escape as gas or form a solid
slag
Slag is a by-product of smelting (pyrometallurgical) ores and used metals. Broadly, it can be classified as ferrous (by-products of processing iron and steel), ferroalloy (by-product of ferroalloy production) or non-ferrous/base metals (by-prod ...
. The refractory lining of the converter also plays a role in the conversion —
clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4).
Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...
linings may be used when there is little
phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
in the raw material, and Bessemer himself used
ganister
A ganister (or sometimes gannister ) is hard, fine-grained quartzose sandstone, or orthoquartzite,Jackson, J. A., 1997, ''Glossary of geology'', 4th ed. American Geological Institute, Alexandria. used in the manufacture of silica brick typically ...
sandstone – this is known as the ''
acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
Bessemer'' process. When the phosphorus content is high,
dolomite Dolomite may refer to:
*Dolomite (mineral), a carbonate mineral
*Dolomite (rock), also known as dolostone, a sedimentary carbonate rock
*Dolomite, Alabama, United States, an unincorporated community
*Dolomite, California, United States, an unincor ...
, or sometimes
magnesite
Magnesite is a mineral with the chemical formula (magnesium carbonate). Iron, manganese, cobalt, and nickel may occur as admixtures, but only in small amounts.
Occurrence
Magnesite occurs as veins in and an alteration product of ultramafic ro ...
, linings are required in the
basic
BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...
Bessemer
limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
process, see
below
Below may refer to:
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Anatomy and sex
* Bottom (BDSM), the partner in a BDSM who takes the passive, receiving, or obedient role, to that of the top or ...
. In order to produce steel with desired properties, additives such as
spiegeleisen
Spiegeleisen (literally "mirror-iron", —mirror or specular; —iron) is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. Spiegeleisen is sometimes also referred to as ''specular pig iron' ...
(a ferromanganese alloy), can be added to the molten steel once the impurities have been removed.
Managing the process
When the required steel had been formed, it was poured into ladles and then transferred into moulds while the lighter slag was left behind. The conversion process, called the "blow", was completed in approximately 20 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 greatly aided the blower in controlling final product quality. After the blow, the liquid metal was recarburized to the desired point and other alloying materials were added, depending on the desired product.
A Bessemer converter could treat a "heat" (batch of hot metal) of 5 to 30 tons at a time. They were usually operated in pairs, one being blown while another was being filled or tapped.
Predecessor processes
![Högbo bruk 07](https://upload.wikimedia.org/wikipedia/commons/c/c8/H%C3%B6gbo_bruk_07.jpg)
By the early 19th century the puddling process was widespread. Until technological advances made it possible to work at higher heats,
slag
Slag is a by-product of smelting (pyrometallurgical) ores and used metals. Broadly, it can be classified as ferrous (by-products of processing iron and steel), ferroalloy (by-product of ferroalloy production) or non-ferrous/base metals (by-prod ...
impurities could not be removed entirely, but the
reverberatory 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 ''rebo ...
made it possible to heat iron without placing it directly in the fire, offering some degree of protection from the impurity of the fuel source. Thus, with the advent of this technology,
coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when dea ...
began to replace
charcoal
Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, cal ...
fuel. The Bessemer process allowed steel to be produced without fuel, using the impurities of the iron to create the necessary heat. This drastically reduced the costs of steel production, but
raw material
A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feedst ...
s with the required characteristics could be difficult to find.
High-quality steel was made by the reverse process of adding carbon to carbon-free
wrought iron
Wrought iron is an iron alloy with a very low carbon content (less than 0.08%) in contrast to that of cast iron (2.1% to 4%). It is a semi-fused mass of iron with fibrous slag Inclusion (mineral), inclusions (up to 2% by weight), which give it a ...
, usually imported from
Sweden
Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...
. The manufacturing process, called the
cementation process
The cementation process is an obsolete technology 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. Derwentcote Steel F ...
, consisted of heating bars of wrought iron together with
charcoal
Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, cal ...
for periods of up to a week in a long stone box. This produced
blister steel
The cementation process is an obsolete technology 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. Derwentcote Steel Fur ...
. The blister steel was put in a crucible with wrought iron and melted, producing
crucible steel
Crucible steel is steel made by melting pig iron (cast iron), iron, and sometimes steel, often along with sand, glass, ashes, and other flux (metallurgy), fluxes, in a crucible. In ancient times steel and iron were impossible to melt using char ...
. 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 (approximately £3,390 to £4,070 in 2008) a
long ton. The most difficult and work-intensive part of the process, however, was the production of wrought iron done in
finery forge
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 ...
s in Sweden.
This process was refined in the 18th century with the introduction of
Benjamin Huntsman
Benjamin Huntsman (4 June 170420 June 1776) was an English inventor and manufacturer of cast or crucible steel.
Biography
Huntsman was born the fourth child of William and Mary (née Nainby) Huntsman, a Quaker farming couple, in Epworth, Li ...
's
crucible steel
Crucible steel is steel made by melting pig iron (cast iron), iron, and sometimes steel, often along with sand, glass, ashes, and other flux (metallurgy), fluxes, in a crucible. In ancient times steel and iron were impossible to melt using char ...
-making techniques, 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 the time needed to make steel of this quality to about half an hour while requiring only the coke needed initially to melt the pig iron. The earliest Bessemer converters produced steel for £7 a
long ton, although it initially sold for around £40 a ton.
"Basic" vs. acidic Bessemer process
Sidney Gilchrist Thomas
Sidney Gilchrist Thomas (16 April 1850 – 1 February 1885) was an English inventor, best known for his role in the iron and steel industry.
Life
Thomas was born at Canonbury, London, and was educated at Dulwich College. His father, a Welshman, w ...
, a Londoner with a Welsh father, was an industrial chemist who decided to tackle the problem of phosphorus in iron, which resulted in the production of low grade steel. Believing that he had discovered a solution, he contacted his cousin,
Percy Gilchrist
Percy Carlyle Gilchrist FRS (27 December 1851 – 16 December 1935) was a British chemist and metallurgist.
Life
Gilchrist was born in Lyme Regis, Dorset, the son of Alexander and Anne Gilchrist and studied at Felsted and the Royal School of ...
, who was a chemist at the
Blaenavon Ironworks
Blaenavon Ironworks is a former industrial site which is now a museum in Blaenavon, Wales. The ironworks was of crucial importance in the development of the ability to use cheap, low quality, high sulphur iron ores worldwide. It was the site ...
. The manager at the time, Edward Martin, offered Sidney equipment for large-scale testing and helped him draw up a patent that was taken out in May 1878. Sidney Gilchrist Thomas's invention consisted of using dolomite or sometimes limestone linings for the Bessemer converter rather than clay, and it became known as the 'basic' Bessemer rather than the 'acid' Bessemer process. An additional advantage was that the processes formed more slag in the converter, and this could be recovered and used very profitably as a phosphate fertilizer.
Importance
![Production fonte fer acier France G-B](https://upload.wikimedia.org/wikipedia/commons/a/a7/Production_fonte_fer_acier_France_G-B.svg)
In 1898, ''
Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...
'' published an article called ''Bessemer Steel and its Effect on the World'' explaining the significant economic effects of the increased
supply
Supply may refer to:
*The amount of a resource that is available
**Supply (economics), the amount of a product which is available to customers
**Materiel, the goods and equipment for a military unit to fulfill its mission
*Supply, as in confidenc ...
in cheap steel. They noted that the expansion of railroads into previously sparsely inhabited regions of the country had led to settlement in those regions, and had made the trade of certain goods profitable, which had previously been too costly to transport.
The Bessemer process revolutionized steel manufacture by decreasing its cost, from £40 per long ton to £6–7 per long ton, 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. Before it was introduced, steel was far too expensive to make bridges or the framework for buildings and thus wrought iron had been used throughout the
Industrial Revolution
The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
. After the introduction of the Bessemer process, steel and wrought iron became similarly priced, and some users, primarily railroads, turned to steel. Quality problems, such as brittleness caused by nitrogen in the blowing air, prevented Bessemer steel from being used for many structural applications.
Open-hearth steel was suitable for structural applications.
Steel greatly improved the productivity of railroads. Steel rails lasted ten times longer than iron rails. Steel rails, which became heavier as prices fell, could carry heavier locomotives, which could pull longer trains. Steel rail cars were longer and were able to increase the freight to car weight from 1:1 to 2:1.
As early as 1895 in the UK it was being noted that the heyday of the Bessemer process was over and that the
open hearth
An open-hearth furnace or open hearth furnace is any of several kinds of industrial Industrial furnace, furnace in which excess carbon and other impurities are burnt out of pig iron to Steelmaking, produce steel. Because steel is difficult to ma ...
method predominated. The ''Iron and Coal Trades Review'' said that it was "in a semi-moribund condition. Year after year, it has not only ceased to make progress, but it has absolutely declined." It has been suggested, both at that time and more recently, that the cause of this was the lack of trained personnel and investment in technology rather than anything intrinsic to the process itself. For example, one of the major causes of the decline of the giant ironmaking company
Bolckow Vaughan
Bolckow, Vaughan & Co., Ltd was an English steelmaking, ironmaking and mining company founded in 1864, based on the partnership since 1840 of its two founders, Henry Bolckow and John Vaughan (ironmaster), John Vaughan. The firm drove the dramat ...
of Middlesbrough was its failure to upgrade its technology. The basic process, the Thomas-Gilchrist process, remained in use longer, especially in Continental Europe, where iron ores were of high phosphorus content and the open-hearth process was not able to remove all phosphorus; almost all inexpensive construction steel in Germany was produced with this method in the 1950s and 1960s.
It was eventually superseded by
basic oxygen steelmaking
Basic oxygen steelmaking (BOS, BOP, BOF, or OSM), also known as Linz-Donawitz steelmaking or the oxygen converter processBrock and Elzinga, p. 50. is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing ...
.
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
Scrap consists of Recycling, recyclable materials, usually metals, left over from product manufacturing and consumption, such as parts of vehicles, building supplies, and surplus materials. Unlike waste, scrap Waste valorization, has monetary ...
steel to be charged, further increasing costs, especially when scrap was inexpensive. Use of
electric arc furnace
An electric arc furnace (EAF) is a furnace that heats material by means of an electric arc.
Industrial arc furnaces range in size from small units of approximately one-tonne capacity (used in foundries for producing cast iron products) up to ab ...
technology competed favourably with the Bessemer process resulting in its obsolescence.
Basic oxygen steelmaking is essentially an improved version of the Bessemer process (decarburization by blowing oxygen as gas into the heat rather than burning the excess carbon away by adding oxygen carrying substances into the heat). The advantages of pure oxygen blast over air blast were known to Henry Bessemer, but 19th-century technology was not advanced enough to allow for the production of the large quantities of pure oxygen necessary to make it economical.
See also
*
Cementation (metallurgy) process
*
Methods of crucible steel production
References
Bibliography
*
External links
*
*
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{{Iron and steel production
English inventions
Steelmaking
Metallurgical processes
Economic history of the United States