gines operate at much higher pressure than Watt’s, they are similar in design. Principles of Operation Early steam engines would be considered upside- down by modern standards. The piston was connected to a rod that emerged from the top ofthe engine, and steam was fed into the cylinder below the piston. A chain connected the piston rod to one end of a piv- oted beam suspended above the engine, and the other end of the beam was connected to a pump that drew water up from the bottom of a mine. The weight of the pump rod was sufficient to pull the pump end of the pivoted beam downward, which caused the other end of the beam to rise and lift the piston up- ward. As the piston rose, steam at just above atmo- spheric pressure flowed from the boiler into the grow- ing space below the piston. When the piston reached the top of its stroke, the valve between boiler and cyl- inder closed, and in Newcomen’s engine water was sprayed into the cylinder. As the water absorbed heat from the steam, the steam condensed, which created a partial vacuum. This vacuum, combined with atmo- spheric pressure acting on the upper side of the pis- ton, caused the piston to move downward. When the piston reached the bottom of its stroke, the steam valve opened again. The steam pressure balanced the atmospheric pressure on the other side of the piston, and the weight of the pump rod again raised the pis- ton to the top of its stroke. Watt recognized that spraying cold water directly into the cylinder not only condensed the steam but also cooled off the cylinder itself. On the next stroke some incoming steam was wasted in reheating the cyl- inder. The separate condenser in Watt’s engine con- densed the steam without chilling the cylinder. This resulted in a dramatic improvement in fuel consump- tion. Watt also closed off the upper side of the piston and provided ahole just bigenough for thepiston rod to pass out. Constant-pressure steam was admitted to the space above the piston, and this steam provided the pressure previously supplied by the atmosphere. Watt’s original purpose here was to eliminate the cooling effect of theatmosphere, but hesoon realized that there was another benefit. Instead of continuing to admit steam at constant pressure during the entire downward stroke, the steam valve could be closed and the steam couldbe allowed toexpand. This furtherre - duced fuel consumption and paved the way for mod - ern expansion steam engines. Applications of the Steam Engine The firstapplications were to drive dewatering pumps in mines and to supply pressurized air for blast fur- naces that produced cast iron. It was soon realized that rotary steam engines could be used to drive all kinds of machinery. Without the invention of the steam engine, the Industrial Revolution would not have occurred in the time and place that it did. Steam engines drove spinning and weaving machines in the textile industry. Ships and railroad locomotives pow- ered by steam engines revolutionized transportation. There were steam-powered farm tractors, automo- biles, and construction machines. Early electric gen- erators were also driven by steam engines. Many of these applications are now powered by electric mo- tors, gasoline and diesel engines, and steam turbines, but it was the steam engine that showed the way. Edwin G. Wiggins Further Reading Barton, D. B. The Cornish Beam Engine: A Survey of Its History and Development in the Mines of Cornwall and Devon from Before 1800 to the Present Day, with Some- thing of Its Use Elsewhere in Britain and Abroad. New ed. Truro, Cornwall, England: Author, 1966. Bray, Stan. Making Simple Model Steam Engines. Rams- bury, England: Crowood, 2005. Briggs, Asa. The Power of Steam: An Illustrated History of the World’s Steam Age. Chicago: University of Chi- cago Press, 1982. Crump, Thomas. A Brief History of the Age of Steam: The Power That Drove the Industrial Revolution. New York: Carroll & Graf, 2007. Marsden, Ben. Watt’s Perfect Engine: Steam and the Age of Invention. New York: Columbia University Press, 2002. Rose, Joshua. Modern Steam Engines. Philadelphia: H.C. Baird, 1886. Reprint. Mendham, N.J.: Astra- gal Press, 2003. Steingress, Frederick M., Harold J. Frost, and Daryl R. Walker. Stationary Engineering. 3d ed. Homewood, Ill.: American Technical, 2003. Web Site How Stuff Works How Steam Engines Work http://www.howstuffworks.com/steam.htm See also: Coal; Electrical power; Industrial Revolu - tion and industrialization; Metals and metallurgy; Steam and steam turbines; Watt, James. 1146 • Steam engine Global Resources Steel Category: Products from resources A variety of related alloys make up the products called “steel.” Since large-scale steel manufacturing processes were developed in the mid-nineteenth century, steel has been essential to the construction and transportation industries. Worldwide raw steel production exceeds 1 billion metric tons a year. Background Steel is produced when iron ore is combined with alloying elements—including carbon, chromium, nickel, manganese, molybdenum, silicon, and tung- sten—and reduced by high heat to a molten state. Immediately after molten steel becomes solid, it is malleable, making it a highly versatile construction material. Steel has been produced with countless al- loys, each of which lends unique characteristics to the finished product. Because steel can be produced relatively cheaply and because it is durable, malleable, strong, corro- sion-resistant, and ductile, itisamong the mostimpor- tant products worldwide, especially in industrial na- tions. Depending on how it is made, it also can be heat-resistant, heat-conductive, and magnetic-perme- able, a versatility that makes it indispensable in build- ing automobiles, locomotives, airplanes, ships, and a host of other products that serve the transportation industry. Its value in the construction of buildings is incalculable. Before steel was mass-produced and de- veloped in specialized ways, the skyscrapers that form the skylines of most major cities could not be built. Steel’s Early History Early iron production dates to about 2000 b.c.e., probably beginning in Anatolia (Turkey). The manu- facture of iron for making weapons, instruments, and various utensils was well established one thousand years later. By 500 b.c.e., the Iron Age had touched all of Western Europe; there is evidence that a century later it had reached China. Wrought iron has a longer history than steel, but some of the early wroughtiron, whose carbon content ranged from 0.07 percent to 0.8 percent, qualified as steel. When iron has a carbon content above 0.3 per - cent, it possesses the qualities of steel. It becomes strong and, when quenched with cold water, very brit - tle. Whenit is reheated, however, inthe process called tempering, the brittleness is reduced, increasing the metal’s malleability substantially. The history of steel dates back three and a half mil- lennia, probably to ancient inhabitants of what is now called Armenia. Sometime around 1500 b.c.e.,itis speculated, a fire raged over a landmass that had iron ore deposits closeto its surface. Asthe iron ore melted and mixed with the elements that surrounded it, cer- tainly silicon and probably at least trace elements of several other minerals, an alloy was formed. When people discovered the properties this alloy had and realized its unique qualities, they devised ways of re- peating the process under controlled conditions. It is thought that the earliest manufactured steel was produced in small ovens or furnaces stoked with charcoal whose carbon mixed with iron ore to form the alloy. The draft that kept the fire blazing probably came from a bellows made from goat skin or from some other readily availablematerial. As air wasblown into the fire, oxygen, still a crucial component of steel- making, became part of the mix. Cementation Cementation, one of the most effective ways of pro- ducing steel, began in Europe in the early seven- teenth century. In this process, wrought iron is mixed with carbon in an environment from which most of the air has been removed. Through this process, the outer edges ofwroughtiron are hardenedto the point that they can be sharpened for use as weapons. Some- times a piece of strong, tempered steel was welded to a low-carbon wrought iron base. The result was a serviceable weapon that had a sharp cutting edge. Al- though much steel at this time was produced by trial and error, some formidable weapons were produced throughout the MiddleAges and intothe seventeenth and eighteenth centuries. Another means of achiev- ing cementation was to stack sheets of soft iron that were carbon-free in alternating layers with sheets of iron with a high carbon content and to heat the mass, then work it into a combined product that was stron- ger than wrought iron. When the cementation process was applied to the mass production of steel in the mid-eighteenth cen- tury, bars of wrought iron were put into clay boxes. Each bar was surrounded by charcoal and put into a furnace, which was closed tightly to limit the amount of air that entered it. The boxes were then heated at high temperatures so that the carbon from the char - Global Resources Steel • 1147 coal mixed with the molten iron to yield a product with sufficient carbon content to qualify as steel. Crucible Method Around 1740, Benjamin Huntsman, a British clock and instrument manufacturer, found that clock springs made through the cementation process were unsuited to the intricate workhe was doing. He exper- imented withmelting steelproduced through cemen- tation in a large retort to assure a more even distribu- tion of carbonand other elementsthat would result in a more standard, homogeneous form of steel. Huntsman cut cemented steel into small pieces that he then melted in a closed clay crucible. After he skimmed off the slag, he poured the remaining mol- ten steel into a mold, where it became solid. Then he could work the resulting ingot into any form he re- quired by reheating and hammering it. His prod- uct was much purer than the steel produced solely through cementation, making it a much better mate- rial than was previously availablefor makingprecision instruments. Bessemer Process The cementation and crucible processes were re- placed in the last half of the nineteenth century by the Bessemer process, invented almost simultaneously in England by Henry Bessemer and in the United States by William Kelly. Bessemer’s English patent was granted in 1856, Kelly’s U.S. patent in the following year. The Bessemer process can be either an acid or a base process, depending on whether the lining of the refractory is acid or base. When an acid such as sand- stone is used, molten steel is made beneath an acid slag that covers the molten surface. In this process, compressed air is blown through holes in the bottom of a pear-shaped converter. Oxidation of most of the carbon, manganese, and silicon occurs. This oxida- tion produces the heat required for the process. The base process invented by Sidney Thomas was not patented until 1879. It works on a principle simi- lar to that of the acid process except that it uses a base such as dolomite or magnesite rather than an acid in the refractory.The resulting steel, made undera basic slag, is absent the phosphorus and most of the sulfur in the original pig iron. The Bessemer process made possible for the first time the mass production of low-cost, high-quality steel, an essential component of most technological progress in the late nineteenth century and through - out most of the twentieth century. The first Bessemer steel factory was established in Michigan in 1864 and within a year was turning out the steel rails that made possible the building and rapid expansion of a trans- continental railway system, an essential link in the chain of westward expansion in the United States. By 1886 the United States, which provided steel rails for the world, was producing about 2.7 million metric tons of steel a year, making it the world’s lead- ing steel manufacturer. The Bessemer process made this possible. It was the chief method of making steel until 1907, when the open-hearth process, which had been gaining in popularity since the earliest days of the Bessemer process, essentially replaced it. Open-Hearth Process The steel industry quickly became so central to the in- dustrial and economic development of the United States and othersteel-producing countries thatexper- imentation was constantly afoot to find new and better methods of producing steel and of refining and im- proving the product. As early as 1856, the year in which the Bessemer process was first patented in Brit- ain, CarlFriedrich von Siemens invented the regener- ative process of heating, later improved upon by his brother Karl Wilhelm. In regeneration, the direction of the gases used to heat furnaces is reversed in an al- ternating pattern so that the heat left by the trapped gases is held and used to preheat gases as they enter the vessel. Theresultis a considerableincrease in tem- perature with a minimal expenditure of fuel. By 1870 an acid furnace that employed this princi- ple was developed in Boston. The heat it produced was sufficient to melt pig iron and scrap steel, remov- ing carbon and undesirable impurities in the molten mass through oxidation. Because the steel was melted on a hearth beneath the factory roof and could be seen, inspected, and sampled through furnace doors, the method came to be called the “open-hearth” pro- cess. In this process, the carbon in the pig iron is oxi- dized by theoxygen in theironore, producing carbon monoxide. Ferromanganese is added for deoxidiza- tion when the carbon content of the molten steel reaches an appropriate level. It is then poured into molds that form it into ingots. The acid open-hearth furnace was soon replaced in the United States by the basic open-hearth fur- nace, whose basic lining was magnesite brick that had magnesite or burned dolomite spread over it. This process was an improvement over the Bessemer pro - 1148 • Steel Global Resources cess because of its ability to remove phos - phorus from the molten steel, a great ad- vantage in the United States, many of whose largest deposits of iron ore were phosphorus-laden. The first commercial application of the basic open-hearth process occurred in Pennsylvania in 1888. Within two years, six- teen such furnaces were operating in the United States; by 1950, nine hundred basic open-hearth furnaces were in operation. By the mid-twentieth century, such fur- naces accounted for 90 percent of the steel production in the United States. This pro- cess had fallen out of favor, however, by 1970, when the basic oxygen process began replacing it in many venues. The open- hearth process was an improvement over the Bessemer processbecause it usedlarger quantities of scrap steel than could be used in Bessemer furnaces. Also, the basic open- hearth process eradicated more impurities from the iron ore it used than earlier pro- cesses had. Basic Oxygen Process The basic oxygen process consists of induc- ing pure oxygen under high pressure to en- ter the furnace through a water-cooled tube at the top of the basic refractory. This process removes impuri- ties from the molten iron, which is then poured as molten steel into a ladle. This method offers the quickest, most economical means of converting mol- ten iron to steel on a large scale. Electric Furnace Method The electric furnace process uses electricity to heat scrap metal in a furnace, thereby reducing the scrap metal to a molten state. This method is advantageous because it uses considerably more scrap metal than any of the previous processes usedinmass-producingsteel. The electric arc furnace, invented in 1899 by Paul Héroult, was first used essentially for making preci- sion instruments. Through the years, however, this furnace was able to produce large quantities of plain carbon steel. The use of the electric-arc furnace accel- erated during WorldWar II, when there was an urgent need to use as much scrap steel as possible. Currently this type of furnace, which has a basic bottom of dolomite or magnesite with basic or silica brick sidewalls and roof, can hold a charge of more than 400 metric tons. Advances in electric delivery and technologyhave madepossible theexpanded use of Héroult-type furnaces, whose popularityhasspread throughout the steelmaking industry. A variation on the electric-arc furnace is the induc- tion furnace, whose use is limitedmostly to producing small quantities of the specialized steel used for mak- ing precision instruments. In this process, a round chamber is surrounded by a copper coil through which electrical current is passed after the furnace has been loaded. As the current vibrates within the cham- ber, extremely high temperatures, sufficient to reduce the charge quickly to a molten state, are produced. Rolling Perhaps the most important modern steel-manufac- turing process is rolling. In this process, steel ingots are removed from their molds in a stripper, after which they are immersed in deep, refractory-lined furnaces and heated to temperatures of nearly 1,100° Celsius. The ingots, after reaching the requisite tem - Global Resources Steel • 1149 Steelworkers at the Steel Works factory in Pittsburgh, Pennsylvania, circa 1905. (The Granger Collection, New York) perature, are then removed from the furnace and taken on an ingot buggy to huge tables in the rolling mill, where they are placed horizontally on the tables for primary rolling. Here the ingots are flattened by passing through two rollers revolving in opposite di- rections at the same speed. The primary mill pro- duces blooms, billets, and slabs that are then taken to other mills to be transformed into the specific steel products that industry requires. Other meansof preparing steel for its eventual spe- cialized uses include drawing, forging, extrusion, and casting. Cold drawing is used to produce sizes that cannot be achievedwith thesame precision bythe var- ious hot-working methods available. Forging, proba- bly the oldest method of steel processing, involves the hammering and shaping of hot metal into the forms in which it can bestbe used. Theextrusion method in- volves a hydraulic process by which hot molten steel is forced under high pressure through a die into a cylin- der at one end that has been shaped into the desired configuration. Casting occurs when molten steel is poured into a mold of a given shape and size that will result, on cooling, in a product of the shape and size desired. R. Baird Shuman Further Reading Eisenhuttenheute, Verein Deutscher, ed. Steel: A Handbook for Materials Research and Engineering.2 vols. New York: Springer, 1992. Hillstrom, Kevin, and Laurie Collier Hillstrom, eds. Iron and Steel.Vol.1inThe Industrial Revolution in America. Santa Barbara, Calif.: ABC-CLIO, 2005. Llewellyn, D. T., and R. C. Hudd. Steels: Metallurgy and Applications. 3d ed. Boston: Butterworth-Heine- mann, 1998. Moniz, B. J. Metallurgy.4th ed. Homewood, Ill.: Ameri- can Technical Publishers, 2007. Narayanan, R., ed. Steel-Concrete Composite Structures: Stability and Strength. New York: Elsevier Applied Science, 1988. Neely, John, and Thomas J. Bertone. Practical Metal- lurgy and Materials of Industry. 6th ed. Upper Saddle River, N.J.: Prentice Hall, 2003. Plowden, David. Steel. New York: Viking Press, 1981. Reutter, Mark. Making Steel: Sparrows Point and the Rise and Ruin of American Industrial Might. Rev. ed. Ur- bana: University of Illinois Press, 2004. Verhoeven,John D. Steel Metallurgy forthe Non-Metallur - gist. Materials Park, Ohio:ASMInternational,2007. Web Sites Industry Canada Primary Metals: Statistics http://www.ic.gc.ca/eic/site/pm-mp.nsf/eng/ h_mm01872.html U.S. Geological Survey Iron and Steel: Statistics and Information http://minerals.usgs.gov/minerals/pubs/ commodity/iron_&_steel U.S. Geological Survey Iron and Steel Scrap: Statistics and Information http://minerals.usgs.gov/minerals/pubs/ commodity/iron_&_steel_scrap U.S. Geological Survey Iron and Steel Slag: Statistics and Information http://minerals.usgs.gov/minerals/pubs/ commodity/iron_&_steel_slag/index.html#mcs See also: Alloys; Bessemer process; Carbon; Iron; Manganese; Minerals, structure and physical proper- ties of; Molybdenum; Oxygen; Steel industry; United States. Steel industry Categories: Obtaining and using resources; products from resources The steel industry is an integral part of industrialized society, providing critical products for infrastructure development, transportation, construction, resource extraction and processing, consumer goods, and more. Steel is highly recyclable, and the industry routinely reprocesses steel scrap into new products. Background Before the nineteenth century, steel was a costly spe- cialty item used primarily for weapons and sharp cut- ting tools. Cast and wrought iron was used for most industrial and structural purposes, although iron products lacked steel’s strength and durability. Discoveries in the mid-1800’s created the possibil- ity for steeltosupplant iron as theindustrialand struc- tural material of choice. In 1855, British inventor Sir Henry Bessemer patented a process for producing steel by blowing air through molten pig iron. A decade 1150 • Steel industry Global Resources later, French engineer Pierre-Émile Martin developed the open-hearth process by using the regenerative furnace (created in the 1850’s by German-born engi- neer Charles William Siemens) for steelmaking. The open hearthproved slower thantheBessemer process and thus was easier to control. It had a greater capac- ity than theBessemer process and couldproduce steel of higher and more uniform quality. The introduction of rapid, inexpensive steelmaking processes accelerated the growth of industries whose expansion had been constrained by the limitations of iron and the impracticability of steel. Steel quickly supplanted iron for the construction of bridges, rail- way tracks, andbuildings.Its strength made itidealfor boilers, turbines, gears, engines, trains, artillery, and warships. Its versatilityled to itsuse in foodcans, print- ing presses, telephone and telegraph systems, and a host of consumer goods. England—home of Bessemer and Siemens— dominated the Steel Age until 1889, when the United States became the world’s chief producerof steel. The availability and affordability of steel helped fuel a rapid westward expansion in the United States, which in turn made more resources available to the steel in- dustry and other burgeoning sectors. The United States remained atthe forefront of globalsteelmaking for the following several decades. World Wars I and II boosted demand for steel tanks, ships, munitions, and, during the latter con- flict, planes. Peacetime growth consumed its share of steel as well, with the proliferation of skyscrapers and other major urbanstructures,large suspension bridges and highways, and consumer goods such as automo- biles and household appliances. During the Cold War years, massive amounts of steel were used for con- structing missile silos and other security facilities. Within a century, steel had been established as an indispensable part of modern life. Its strength and versatility had made it essential for infrastructure, transportation, energydelivery, construction, and key consumer goods. A population’s steel consumption per capita became a common indicator of its prosper- ity, and steel industry performance became an impor- tant economic indicator. Technology Changes and Related Trends Bessemer and open-hearth steelmaking dominated the early decades of the modern steel industry. Open- hearth furnaces proved less expensive to operate and more flexible than Bessemer converters, as they could produce thousands of different grades of steel in larger quantities and of a better and more uniform quality. The Bessemer converter lost ground to open- hearth facilities in the early 1900’s, although in the United States, Bessemers remained in use for spe- cialty products such aspipesteel well into the1960’s. The advent of the electric arc furnace in the first decade of the twentieth century made possible spe- cialized alloy steels, as its operation could be regu- lated more closely than that of the Bessemers or open hearths. Electric arc furnaces quickly gained a foot- hold in steelmaking. Electric power helped the indus- try to evolve in other significant areas. Electric rolling mills yielded a vastly more refined and uniform prod- uct than their steam-driven predecessors. Increased mechanization made possible by powerful electric cranes and other equipment allowed furnace size and capacity to grow. During the U.S. steel industry’s heyday, the indus- try pioneered the development of integrated steel plants, where oreis received, processedinto steel,and shipped out from a single large facility incorporating furnaces, coke ovens, rolling mills, and foundries. American steel companies were also the first to insti- tute work shifts that kept plants operating twenty-four hours a day. These innovative approaches to manufac- turing, along withbountiful domestic supplies ofcoal, iron ore, limestone, and immigrant labor, helped the United States to become and remain the world’s lead- ing steel producer through much of the twentieth century. In the 1950’s, Austria introduced a new process to the industry, basic oxygen steelmaking. A refine- ment of Bessemer’s technique, it involved blowing high-purity oxygen through molten pig iron. The oxygen process could produce three times as much high-quality, low-nitrogen steel in an hour as an open- hearth furnace. Its high productivity made it an ap- pealing option for Europe and Japan as they rebuilt their industries in the wake of World War II. Oxygen steelmaking took longer to gain popularity in the United States; it did not overtake the open-hearth process until the 1960’s. Another postwar innovation was continuous cast- ing, a process in which molten steel is solidified into a semifinished form before being rolled in a finishing mill. Through continuous casting, the industry was able to reduce its scrap generation, improve quality, and reduce costs. American “big steel” maintained its grip on the Global Resources Steel industry • 1151 world market until 1959, when a protracted steel- workers’ strikeled customersto foreign suppliers. Do- mestic and foreign “minimills”—small plants using electric arc furnaces and continuous-casting methods to manufacture steel from steel scrap—also captured a portion of the market from the large integrated plants. Steel scrap prices were low in the 1960’s, partly because of scrap’s unsuitability as a primary feedstock for oxygen steelmaking, which provided an opportu- nity for minimills to proliferate. By the late 1970’s, several factors—including out- moded equipment, high wages, increased competi- tion, decreased demand, declining product quality, reduced availability of high-grade domestic iron ore, compliance costs associated with environmental regu- lations and safety standards, and the energy crisis— had caused a sharp decline in the traditional U.S. steel industry.In the 1980’s, the industry experienced slashed wages and benefits, layoffs, plant closures, and buyouts, not only in the United States but also among its chief competitors in Europe, Canada, and Japan. By contrast, new state-subsidized mills in Bra- zil, South Korea, Argentina, and Mexico thrived. Low wages in those countries and the high value of the American dollar made their product an economical alternative to that of the world steel giants. Production and Consumption At the end of the twentieth and the beginning of the twenty-first century, steel production was on the rise in developing countries, notably China, South Korea, India, and Brazil. In 2007, global crude steel produc- tion was 1.3 billion metric tons (compared to about 200 million metric tons in 1950 and 595 million met- ric tons in 1970). In 2007, the top-producing country was China, which, at 489.2 million metric tons, con- tributed 36.4 percent of the global total. Other top producers were Japan(120.2 million metrictons), the United States (98.2 million metric tons), and Russia (72.4 million metric tons). More than one-half of the world total (56.1 percent) was produced in Asia. Oxy - gen steelmaking processes predominated in China, 1152 • Steel industry Global Resources At the ArcelorMittal plant in Germany, a lone forklift piles steel rolls onto railway cars. (Bloomberg via Getty Images) Japan, and Russia, while most of the steelmaking in the United States was in electric arc furnaces. Of the total global production, 66.3 percent came from oxy- gen steelmaking, 31.2 percent came from electrical furnaces, and 2.5 percent was from open-hearth fur- naces. China was also the top consumer of finished steel in 2007. It led world use at 408.3 million metric tons, or 33.8 percent of the global total. The United States was a distant second at 108.2 million metric tons. There were 1 billion metric tons of finished steel products consumed worldwide, or 0.1942 metric ton, per capita. Thegreatest apparent percapita use wasin South Korea (1.143 metric tons) and Taiwan (0.782 metric ton). Sustainability Resources used in steel production include iron ore, limestone, dolomite, zinc ore, coal, natural gas, oil, and water. In 2006, the worldsteel industry consumed approximately 1.8 billion metric tons of iron ore. These resources are nonrenewable. However, unlike many other materials,steel can berecycledrepeatedly without losing its properties. Cars, household appli- ances, building materials, cans, and other steel prod- ucts are routinely recycled at the end of their useful lives. Ferrous scrap consumption in 2007 was an esti- mated 479 million metric tons. Recycling scrap steel not only keeps it out of landfills but also saves energy: Producing steel from scrap instead of iron ore con- sumes 60 percent less energy. Global Resources Steel industry • 1153 Data from the U.S. Geological Survey, . U.S. Government Printing Office, 2009.Source: Mineral Commodity Summaries, 2009 123,000,000 14,000,000 94,000,000 312,000,000 Metric Tons of Metal 600,000,000500,000,000400,000,000300,000,000200,000,000100,000,000 United States South Korea Russia Japan Italy Germany Ukraine United Kingdom Other countries 513,000,000 19,000,000France China Brazil 48,000,000 32,000,000 74,000,000 55,000,000 40,000,000 36,000,000 Top Steel Producers, 2008 Steel is a versatile material, and steel products boast a plethora of forms, thicknesses, compositions, and properties. Innovations in steelmaking technol- ogy and product design allow the industry to address the specific demands of its customers while reducing energy use and consumption of raw materials. A mun- dane but notableexample is the steelbeverage can. As of 2002, the mass of a typical steel beverage can was about 75 percent less than it was for a can of com- parable size made in the 1960’s. The decrease was achieved through steelmaking technologies that pro- duced a more formable yet sufficiently strong steel.By meeting consumer needs while using less steel, pack- aging manufacturers increase their resource and en- ergy efficiency. Similarly, an international consortium of sheet steel producers has worked to improve another widely used steel product, the automobile. The consortium has piloted a series of design initiatives to develop ultralight steel automobile bodies, doors, hoods, and suspension systems for the automobile industry. This ongoing effort has yielded a number of concepts that have found applications in production vehicles. Re- ducing vehicle weight without sacrificing safety or affordability enables steelmakers and their automo- bile-manufacturer customers to satisfy an environ- mentally aware public with improved gas mileage, re- duced emissions, and—at the end of a decade or more of use—a highly recyclable product. Karen N. Kähler Further Reading Cooney, Stephen. Steel Industry: Price and Policy Issues. Hauppauge, N.Y.: Nova Science, 2008. Hall, Christopher. Steel Phoenix: The Fall and Rise of the U.S. Steel Industry. New York: St. Martin’s Press, 1997. Madar, Daniel. Big Steel: Technology, Trade, and Survival in a Global Market. Vancouver: UBC Press, 2009. Rudacille, Deborah. Roots of Steel: The Boom and Bust of an American Mill Town. New York: Pantheon Books, 2010. Web Site World Steel Association http://www.worldsteel.org See also: Bessemer process; Carnegie, Andrew; Iron; Mittal, Lakshmi; Smelting; Steel. Stephenson, George Category: People Born: June 9, 1781; Wylam, Northumberland, England Died: August 12, 1848; Chesterfield, Derbyshire, England The technological breakthroughs in railway and loco- motive engineering brought to fruition by Stephenson’s efforts changed the face and direction of the Industrial Revolution by greatly accelerating the speed and effi- ciency for the transport of raw-material resources and finished goods and by generating demand for greater fuel and construction material. Biographical Background George Stephenson came from an impoverished back- ground; his father was employed as a manual laborer at a colliery. Stephenson had no educationuntil 1798, when, at the age of seventeen, he attended classes at night while laboring as a colliery worker during the daylight hours. He married Frances Henderson in 1802; the couple had one surviving child, a son named Robert, before Frances died in 1806. In 1818, Stephen- son designed a miner’s safety lamp, a success tarnished by a lengthy legal battle with Sir Humphry Davy, who alleged that Stephenson had stolen his idea. The final ruling confirmed that both men had legitimately and independently arrived at the invention. Though Stephenson did not invent the steam loco- motive, he did pioneer locomotive design, including (with his son) the design for the famous Rocket loco- motive (1829). Railway engineering was the field in which he made his most innovative contributions. He standardized the rail gauge system and his construc- tions included the first totally machine-powered rail- way, the Hetton Colliery-to-Sunderland line (1820), as well as the Stockton-to-Darlington line (1825) and the Liverpool-to-Manchester line (1830). The latter remains Stephenson’s most notable accomplishment, though he spent the rest of his years designing rail- ways and bridges, producing locomotives for the Brit- ish and American markets, and coal mining in North- ern England. Impact on Resource Use The technological advances stemming from Stephen - son’s achievements called inevitably for the consump - 1154 • Stephenson, George Global Resources tion of great amounts of fuel resources, mainly coal, for steam power production as well as for iron, lum- ber, bricks, and mortar, all of which were needed in rail-line, locomotive, and rail-car (rolling-stock) con- struction. The overall long-term impact that the rail- ways had on resource supplies in England is debated by historians. However, when translated over the cen- tury following Stephenson’s heyday—and on a global scale as rail technology became international in scope and application—the pressure oncoal, iron, and lum- ber resources was significant. In turn, the implemen- tation of locomotive technology and the laying out of rail paths enabled more rapid transport; widespread distribution of these coal, iron, and lumber resources; and the more efficient exploitation of coal. Coal came to be employed to an even greater de - gree when the use of cast iron gave way to wrought iron for making rails; the cast iron tended to break more readily under pressure. Stephenson himself made the switch to wrought iron with the construc- tion of the Stockton-to-Darlington railway. Coal was used extensively in the puddling process for wrought- iron production. Raymond Pierre Hylton See also: Coal; Industrial Revolution and industrial- ization; Mineral resource use, early history of; Steam engine; Steel; Transportation, energy use in. Stockholm Conference Categories: Laws and conventions; historical events and movements Date: June, 1972 The Stockholm Conference was the first multilateral environmental conference and the forerunner to subse- quent conferences, treaties, and agreements on specific environmental issues. Its major purpose was to focus attention on the preservation of the Earth’s genetic re- sources. Background The United Nations (U.N.) Conference on the Hu- man Environment, known as the Stockholm Confer- ence, was convened by the United Nations General Assembly in Stockholm, Sweden, in June, 1972. The conference was the result of a 1967 initiative by Swe- den and a December 3, 1968, U.N. General Assembly resolution that called on all the states to convene in one forum in order to focus attention on increasing worldwide environmental problems and to formulate a plan for cleaning up pollution and for conserving and protecting the genetic and natural resources of the Earth. Prior to the conference, a seminar on issues con- cerning the environment was heldat Founex, Switzer- land, in June, 1971, to settle one of the major disputes facing the countries that were to meet in Stockholm: The developed countries were interested in resource conservation, while the developing countries were anxious to industrialize and considered environmen - tal issues a secondary concern. When pressed to pre - serve the large part of the Earth’s biological resources Global Resources Stockholm Conference • 1155 George Stephenson was an important inventor during the Indus- trial Revolution. (Library of Congress) . Stephenson, George Global Resources tion of great amounts of fuel resources, mainly coal, for steam power production as well as for iron, lum- ber, bricks, and mortar, all of which were needed. the large part of the Earth’s biological resources Global Resources Stockholm Conference • 1155 George Stephenson was an important inventor during the Indus- trial Revolution. (Library of Congress) . pro - 1148 • Steel Global Resources cess because of its ability to remove phos - phorus from the molten steel, a great ad- vantage in the United States, many of whose largest deposits of iron ore were phosphorus-laden. The