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Introduction to the First Industrial Revolution
TWO CENTURIES OF REVOLTIONARY CHANGE
The Industrial Revolution
Iron and Steel Manufacture
The development of the railway stimulated the economy in two important ways. First, the advent of cheap and efficient transport lowered the carriage cost of goods. This meant that goods were cheaper in the shops and this increased the demand. The increase in demand led to the expansion of factories which required more energy. The prime energy source at the time was coal. As the Industrial Revolution began to speed up, the need for coal grew because it provided power for the factory engines, steam powered ships and steam locomotives. Second, the demand for iron increased. Iron was needed to make the railway tracks, steam locomotives and the giant Watt steam engines that pumped the mines and provided energy to run factory machinery. At a later stage, iron was needed to construct the steamships.
The developers of the early steam engines and steam railways would never have been so successful without parallel developments taking place in the iron industry. Without the ironmasters' expertise in creating new methods of iron casting and working iron, it would have been impossible to have produced steam power in the first place. All of these developments which drove the Industrial Revolution were dependent on each other for their success. New inventions in one field led to advancements in another. These, in turn, stimulated further research and development.
The iron industry began in forested areas since trees were necessary to make the fuel, charcoal. It was cheaper to move iron to the iron works than to move the vast amounts of charcoal needed. When ironworking and shipbuilding caused the forests to shrink rapidly, it became necessary to search for an alternative fuel. Iron was made by smelting iron ore or heating the ore up to melting point. The liquid iron was then cast into ingots, called pigs. The pig iron could then either be reheated until it was molten and cast into moulds, or heated and hammered into bars of wrought iron. Of the two, wrought iron was more malleable and less brittle. Attempts had been made to use coal in the smelting process, but the sulphur in the coal produced an iron which was too brittle for use.
In 1709, an ironmaster in Coalbrookdale, Abraham Darby I, succeeded in producing cast iron using coal. He discovered a process whereby coal was first turned into coke. When coal is turned into coke most of the sulphur is lost as sulphurous gases. The coke could then be used in the smelting process to produce iron. Darby kept his discovery a secret and passed it on only to the next generation of Darbys. His son, Abraham Darby II, and his grandson, Abraham Darby III, eventually perfected his method.
Because they kept the secret, the idea of smelting iron using coke did not become widespread until the second half of the 18th century. The Darby's method of producing iron could only be used for cast iron. The search was still on for a better and cheaper method of producing both wrought iron and steel. Until that time, steel had been very expensive to produce and its uses were limited.
It was Henry Cort who, in 1783, discovered an economic method of producing wrought iron. His 'puddling furnace' produced molten iron that could be rolled straight away, while it was still soft, into rails for railways, pipes, or even sheet iron for shipbuilding.
The History of Iron and Steel Manufacture
Iron was first extracted from its ores over 5000 years ago. Until the 18th century, charcoal was used as the reducing agent. By the early 18th century, charcoal was in short supply and had become expensive. It took 200 acres of forest to supply one iron works for one year, and iron was in demand.
Abraham Darby I
Abraham Darby I owned an iron works at Coalbrookdale in Shropshire. His iron works made everything from domestic pots to the huge iron cylinders needed for Newcomen's steam engine. In 1709, when he was 31 years old, Darby developed a new process for smelting iron. This new process made pig iron, and it used coke instead of charcoal. The demand for coke increased, as did the demand for Newcomen's steam engines since they were used to pump water out of coal mines. Although coke was the cheaper option, it took another 50 years before it completely replaced charcoal.
Benjamin Huntsman, a 36 year old clockmaker, made steel, in small quantities, as early as 1740. He did not "discover" steel, however. In 334 B.C., Aristotle had described Damascus steel which had been used to make swords. Huntsman made steel by putting molten iron into earthenware crucibles and then heating it, while excluding air at the same time.
In 1762, Matthew Boulton set up the Soho Manufactory in Birmingham. His factory made iron which was transformed into useful articles, such as buckles and bolts. What made Boulton's factory so special was that it was large and situated near the Midlands' coalfields. Most of the other iron works at that time were small affairs and built close to forests, since they still depended on charcoal.
Henry Cort was from Lancaster in Lancashire. His work for the Navy took him to Plymouth. In 1775, after ten years in the west country, he retired from his naval job and bought a small ironworks just outside the city. His innovations in the iron industry earned him the name "Father of the Iron Trade". Cort invented a new process to make wrought iron. His method was called the "puddling process". He also developed a rolling mill to produce wrought iron bars. He patented his inventions in 1783. In Cort's process, the melted pig iron was heated with air and iron ore. The resulting pasty metal was then hammered to remove some of the impurities (or slag). To make iron bars, the molten metal was passed through grooved rollers. As a result of Cort's method, wrought iron production increased by 400% over the next twenty years. Unfortunately, Cort lost his patent when his business partner was discovered to have financed the project using stolen money. Cort went bankrupt and lived the rest of his life on a small pension.
Sir Henry Bessemer
Henry Bessemer was a self-educated man who came from Hertfordshire in England. In 1856, he developed a "basic oxygen converter" to change pig iron into steel. In 1879, Bessemer received a knighthood and a fellowship in the Royal Society for his contribution to the iron and steel industries. Bessemer's process was only suitable for British iron ore, since the ore did not contain much phosphorous. It was not until 1879, that the more advanced Percy Gilchrist and S.G.Thomas method, which was suitable for phosphoric ores as found in Europe, was adopted by the continental steel makers, such as Alfred Krupp in Germany.
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