(Edited from Wikipedia)

SUMMARY

The Bessemer process was the first inexpensive industrial process for the mass production of from molten pig before the development of the . The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron. The oxidation also raises the temperature of the iron mass and keeps it molten.

Related decarburizing (removing ) with air processes had been used outside Europe for hundreds of years, but not on an industrial scale. One such process has existed since the in East Asia, where the scholar describes 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 , who took out a patent on the process in 1856. The process was said to be independently discovered in 1851 by the American inventor , though there is little to back up this claim.

HISTORY

Sir Henry Bessemer described the origin of his invention in his autobiography written in 1890. During the outbreak of the Crimean War, many English industrialists and inventors became interested in military technology. According to Bessemer, his invention was inspired by a conversation with Napoleon III in 1854 pertaining to the steel required for better .

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

1 steel in the massive quantities required for artillery and by October he filed his first patent related to the Bessemer process. He patented the method a year later in 1856.

According to his autobiography Bessemer was working with an ordinary but during a test, some pieces of were jostled off the side of the ladle, and were left above the ladle in the furnace's heat. When Bessemer went to push them into the ladle, he found that they were steel shells: the hot air alone had converted the outsides of the iron pieces 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. Instead, the oxygen in the forced air ignited and carbon impurities in the iron, starting a positive feedback loop. As the iron became hotter, more impurities burned off, making the iron even hotter and burning off more impurities, producing a batch of hotter, purer, molten iron, which converts to steel more easily.

Henry Bessemer

Bessemer licensed the patent for his process to four , 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. 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 realized 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 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% which was part of the air blast passing through the steel.

Bessemer was sued by the patent purchasers who couldn't get it to work. In the end Bessemer set up his own steel company because he knew how to do it, even though he could not convey it to his patent users. Bessemer's company became one of the largest in the world and changed the face of steel making.

2 The solution was first discovered by English metallurgist , who had carried out thousands of experiments in the . His method was to first burn off, as far as possible, all the impurities and carbon, then reintroduce carbon and by adding an exact amount of . 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.

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 from 1858, initially using imported pig iron from . This was the first commercial production.

SIGNIFICANCE AND IMPACT

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 had been used throughout the . 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.

Bessemer in America

While visiting Europe to obtain information on shipbuilding, armor, and armaments from 1862 to 1863, Alexander Lyman Holley visited Bessemer's Sheffield works, and

3 expressed interest in licensing the process for use in the US. Upon returning to the US, Holley met with noted inventor John Ericsson, who referred Holley to a pair of businessmen who had helped him build the Civil War ironclad USS Monitor, John F. Winslow and John Augustus Griswold. With Winslow and Griswold's support, Holley returned to in 1863, and paid Bessemer £10,000 to license the technology.

The trio began setting up a mill in Troy, New York 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, 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 , 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 and the Union Iron Works. Holley built the new for Carnegie, and continued to improve and refine the process. The new mill, known as the Edgar Thomson Steel Works, opened in 1875, and started the growth of the United States as a major world steel producer.

ANDREW CARNEGIE

Andrew Carnegie (November 25, 1835 – August 11, 1919) was a Scottish-American industrialist.

Carnegie led the expansion of the American steel industry in the late 19th century and is often identified as one of the richest people and Americans ever. He built a leadership role as a philanthropist for the United States and the British Empire. During the last 18 years of his life, he gave away to charities, foundations, and universities about $350 million (in 2015 share of GDP, $78.6 billion)—almost 90 percent of his fortune. His 1889 article proclaiming "The Gospel of Wealth" called on the rich to use their wealth to improve society, and it stimulated a wave of philanthropy.

Carnegie was born in Dunfermline, Scotland, and emigrated in 1848 to the United States with his parents. Carnegie started work as a telegrapher and by the 1860s had investments in railroads, railroad sleeping cars, bridges and oil derricks. He accumulated further wealth as a bond salesman raising money for American enterprise in Europe. He built 's , which he sold to J.P. Morgan in 1901

4 for $480 million. It became the U.S. Steel Corporation. After selling Carnegie Steel, he surpassed John D. Rockefeller as the richest American for the next couple of years.

Carnegie devoted the remainder of his life to large-scale philanthropy, with special emphasis on local libraries, world peace, education and scientific research. With the fortune he made from business, he built Carnegie Hall and the Peace Palace and founded the Carnegie Corporation of New York, Carnegie Endowment for International Peace, Carnegie Institution for Science, Carnegie Trust for the Universities of Scotland, Carnegie Hero Fund, Carnegie Mellon University and the Carnegie Museums of Pittsburgh, among others.

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