Continuous casting called strand casting, is the process whereby molten metal is solidified into a "semifinished" billet, bloom, or slab for subsequent rolling in the finishing mills. Prior to the introduction of continuous casting in the 1950s, steel was poured into stationary molds to form ingots. Since "continuous casting" has evolved to achieve improved yield, quality and cost efficiency, it allows lower-cost production of metal sections with better quality, due to the inherently lower costs of continuous, standardised production of a product, as well as providing increased control over the process through automation. This process is used most to cast steel. Aluminium and copper are continuously cast. Sir Henry Bessemer, of Bessemer converter fame, received a patent in 1857 for casting metal between two counter-rotating rollers; the basic outline of this system has been implemented today in the casting of steel strip. Molten metal is tapped into the ladle from furnaces. After undergoing any ladle treatments, such as alloying and degassing, arriving at the correct temperature, the ladle is transported to the top of the casting machine.
The ladle sits in a slot on a rotating turret at the casting machine. One ladle is in the'on-cast' position while the other is made ready in the'off-cast' position, is switched to the casting position when the first ladle is empty. From the ladle, the hot metal is transferred via a refractory shroud to a holding bath called a tundish; the tundish allows a reservoir of metal to feed the casting machine while ladles are switched, thus acting as a buffer of hot metal, as well as smoothing out flow, regulating metal feed to the molds and cleaning the metal. Metal is drained from the tundish through another shroud into the top of an open-base copper mold; the depth of the mold can range from 0.5 to 2 metres, depending on the casting speed and section size. The mold is water-cooled to solidify the hot metal directly in contact with it, it oscillates vertically to prevent the metal sticking to the mold walls. A lubricant is added to the metal in the mold to prevent sticking, to trap any slag particles—including oxide particles or scale—that may be present in the metal and bring them to the top of the pool to form a floating layer of slag.
The shroud is set so the hot metal exits it below the surface of the slag layer in the mold and is thus called a submerged entry nozzle. In some cases, shrouds may not be used between mold; some continuous casting layouts feed several molds from the same tundish. In the mold, a thin shell of metal next to the mold walls solidifies before the middle section, now called a strand, exits the base of the mold into a spray chamber; the bulk of metal within the walls of the strand is still molten. The strand is supported by spaced, water-cooled rollers which support the walls of the strand against the ferrostatic pressure of the still-solidifying liquid within the strand. To increase the rate of solidification, the strand is sprayed with large amounts of water as it passes through the spray-chamber. Final solidification of the strand may take place, it is here. This describes a'curved apron' casting machine. In a curved apron casting machine, the strand exits the mold vertically and as it travels through the spray-chamber, the rollers curve the strand towards the horizontal.
In a vertical casting machine, the strand stays vertical. Molds in a curved apron casting machine can be straight or curved, depending on the basic design of the machine. In a true horizontal casting machine, the mold axis is horizontal and the flow of steel is horizontal from liquid to thin shell to solid. In this type of machine, either strand or mold oscillation is used to prevent sticking in the mold. After exiting the spray-chamber, the strand passes through straightening rolls and withdrawal rolls. There may be a hot rolling stand after withdrawal to take advantage of the metal's hot condition to pre-shape the final strand; the strand is cut into predetermined lengths by mechanical shears or by travelling oxyacetylene torches, is marked for identification, is taken either to a stockpile or to the next forming process. In many cases the strand may continue through additional rollers and other mechanisms which may flatten, roll or extrude the metal into its final shape. Aluminium and copper can be cast horizontally and can be more cast into near net shape strip, due to their lower melting temperatures.
Casting machines are designated to be bloom or slab casters. Slab casters tend to cast sections that are much wider than thick: Conventional slabs lie in the range 100–1600 mm wide by 180–250 mm thick and up to 12 m long with conventional casting speeds of up to 1.4 m/minute. Wider slabs are available up to 3250×150 mm Thick slabs are available up to 2200×450 mm at a specific steel facility, generically ranging from 200mm to 300mm Thin slabs: 1680×50 mm at a specific facility, generically ranging from 40mm to 11
Edgar Thomson Steel Works
The Edgar Thomson Steel Works is a steel mill in the Pittsburgh area communities of Braddock and North Braddock, United States. It has been active since 1872, it is owned by U. S. Steel and is known as Mon Valley Works – Edgar Thomson Plant on its official website; the mill occupies the historic site of Braddock's Field, on the banks of the Monongahela River east of Pittsburgh. On July 9, 1755, in the Battle of the Monongahela and Indian forces from Fort Duquesne defeated the expedition of British General Edward Braddock, who himself was mortally wounded. Braddock's Field was the site of a rally of rebellious militiamen and farmers during the Whiskey Rebellion, prior to a massive march on the town of Pittsburgh on August 1, 1794; the site is on the banks of the Monongahela, which provides cost-effective, riverine transportation of coke and finished steel products. The Edgar Thomson Steel Works was designed and built because of the Bessemer process, the first inexpensive industrial process for the mass production of steel.
In the process, air blowing through the molten iron removed impurities via oxidation. This took place in the Bessemer converter, a large ovoid steel container lined with clay or dolomite. In the summer of 1872, while in Europe, Andrew Carnegie learned about the Bessemer process, he returned to Pittsburgh with plans to build his own Bessemer plant. Some of the partners and connected people were William Coleman, Andrew Kloman, Henry Phipps, David McCandless, Wm. P. Shinn, John Scott, David A. Stewart, James Robb Wilson and Thomas Carnegie; the firm was known as Carnegie, McCandless, Company. The plant was named after J. Edgar Thomson, the president of the Pennsylvania Railroad. Carnegie Brothers and Company was created by the consolidation of the steel businesses owned by Andrew Carnegie in the early 1880s; those steel and coke works that were consolidated were: Sciota Ore Mines Union Iron Mills Edgar Thomson Steel Works Lucy Furnaces Monastery Coke Works Larimer Coke WorksThe merging of these separate business operations into one resulted in the newly formed company owning an interest of nearly $5 million.
On January 1, 1873, ground work began on the Edgar Thomson Steel Works in Braddock Twp. It has been estimated; the mill was built by Alexander Lyman Holley, who found a manager to run the mill, Capt. William Jones, a Civil War veteran. On August 22, 1875, the Edgar Thomson Steel Works' hulking Bessemer converter produced its first heat of liquid steel, destined to become 2,000 steel rails for the Pennsylvania Railroad. Within one year of beginning production the mill was able to create 32,228 tons of steel rail; the district was known as Bessemer incorporated as North Braddock. The plant's first general superintendent, William R. Jones, described the steel mill writing, "This is the most powerful rail mill in the country. With continual improvements in production the mill was capable of producing 225 tons of steel rails per day. By the late 1880s James Gayley took over as manager of the plant. In 1892, the workers of the plant took part in one of the most serious strikes in U. S. history. The Homestead Strike arose when Henry Clay Frick, an associate and partner of Carnegie, took over while Carnegie traveled to Scotland.
Frick attempted to cut the wages of the steel workers. The steelworkers at the Duquesne and Edgar Thomson Works joined the strike and shut their mills down in sympathy. Frick took extreme measures, he brought in thousands of strikebreakers. When he sent in 300 Pinkerton guards to protect the strikebreakers, a riot broke out, resulting in 10 deaths and thousands of injuries. To prevent any further bloodshed, the governor, Robert Pattison, sent two brigades to stop the fighting. Carnegie, McCandless and Company recommenced operations with non-union immigrant workers. In 1901, Carnegie sold the Carnegie Steel Company, including the Edgar Thomson Works, to J. P. Morgan, Elbert H. Gary and other investors, as part of the foundation of U. S. Steel. In October, 1984 a Merrill Lynch analyst infamously predicted that U. S. Steel would close Thomson within a few years; the plant survived the collapse of the steel industry in the 1980s, which shuttered famous plants, like the Homestead Steel Works in Homestead, or the National Tube Works in Mckeesport, became the last integrated mill in the valley, an area which once contained 90,000 people employed in the basic steel industry.
Today, two blast furnaces continue in operation at the Edgar Thomson Steel Works, which remains part of U. S. Steel. In 2005, the mill produced 2.8 million tons of steel, equal to 28% of U. S. Steel's domestic production; the mill employs about 900 persons, some of whom belong to the second or third generations of their families to work in the mill. Among improvements to its physical plant is a $250 million continuous caster, which converts liquid steel directly into slabs, installed in 1992. In April 1995, the mill was designated a historic landmark by ASM International, a society that honors works of structural engineering. Other structures that have been honored by the society include the Statue of Liberty and the Eiffel Tower. Historic American Engineering Record No. PA-384, "U. S. Steel Edgar Thomson Works, Along Monongahela River, Allegheny County, PA", 3 photos, 1 color transparency, 85 data pages, 1 photo caption page Historic pictures and schematics of the area's rail service U. S. Steel Website — Facilities
The Bessemer process was the first inexpensive industrial process for the mass production of steel from molten pig iron before the development of the open hearth furnace. The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron; the oxidation raises the temperature of the iron mass and keeps it molten. Related decarburizing 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 11th century in East Asia, where the scholar Shen Kuo 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, who took out a patent on the process in 1856. The process was said to be independently discovered in 1851 by the American inventor William Kelly, though there is little to back up this claim.
The process using a basic refractory lining is known as the "basic Bessemer process" or Gilchrist–Thomas process after the English discoverers Percy Gilchrist and Sidney Gilchrist Thomas. 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 innovated a "partial decarbonization" method of repeated forging of cast iron under a cold blast. Sinologist Joseph Needham 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 in 1075, when he visited Cizhou. Hartwell states that the earliest center where this was practiced was the great iron-production district along the Henan–Hebei 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 developed the crucible technique for steel manufacture, at his workshop in the district of Handsworth in Sheffield. 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; the Japanese may have made use of a Bessemer-type process, observed by European travelers in the 17th century. The adventurer Johan Albrecht de Mandelslo 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, Madelslo did not visit Japan, so his description of the process is 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 plausible.
In the early 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; when Bessemer's patent for the process was reported by Scientific American, Kelly responded by writing a letter to the magazine. In the letter, Kelly states that he had 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."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 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 and by October he filed his first patent related to the Bessemer process, he patented the method a year in 1856. Bessemer licensed the patent for his process to four ironmasters, 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 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 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 remained. However, despite spending tens of thousands of poun
Homestead Steel Works
Homestead Steel Works was a large steel works located on the Monongahela River at Homestead, Pennsylvania in the United States. The company developed in the nineteenth century as an extensive plant served by tributary coal and iron fields, a railway 425 miles long, a line of lake steamships; the works were the site of one of the more serious labour disputes in U. S. history, which became known as the Homestead Strike of 1892. The steel works were first constructed in 1881. Andrew Carnegie, bought the 2 year old Homestead Steel Works in 1883, integrated it into his Carnegie Steel Company. A series of industrial disputes over wages, working hours and contracts occurred in the early years of the works, leading to the Homestead Strike, an industrial lockout and strike which began on June 30, 1892, culminating in a battle between strikers and private security agents on July 6, 1892; the battle was one of the most violent disputes in U. S. labor history and the final result was a major defeat for the union and a setback for their efforts to unionize steelworkers.
In 1896, Carnegie built the Carnegie Library of Homestead in nearby Munhall as part of concessions to the striking workers. In 1901, Carnegie sold his operations to U. S. Steel. On January 6, 1906 it was announced that the company would undergo upgrades and expansions worth seven million dollars The workforce peaked at 15,000 during World War II. William J. Gaughan was a Senior Designer of Operations Planning and Control at the company who developed computer systems to aid in automation of various operations. Throughout his management career, Gaughan had developed an interest in the history of Homestead Steel Works and began to collect photos and pamphlets regarding the company; the plant closed in 1986 because of a severe downturn in the domestic steel industry, from which the industry still hasn't recovered. A few remnants of the steel works were not destroyed; as of its opening in 1999, the land is home to an outdoor shopping center. It is home to Sandcastle Waterpark. Homestead Strike Carrie Furnace Media related to Homestead Steel Works at Wikimedia Commons Pittsburgh Post-Gazette retrospective Travel Channel video 1 Travel Channel video 2 Images from Historic Pittsburgh New York Times article Historic American Engineering Record No.
PA-200, "U. S. Steel Homestead Works" — index page + history. HAER No. PA-200-A, "U. S. Steel Homestead Works, Blast Furnace Plant" HAER No. PA-200-B, "U. S. Steel Homestead Works, 45-inch Plate Mill" HAER No. PA-200-C, "U. S. Steel Homestead Works, 48-inch Plate Mill" HAER No. PA-200-D, "U. S. Steel Homestead Works, 100-inch Plate Mill" HAER No. PA-200-E, "U. S. Steel Homestead Works, 140-inch Plate Mill" HAER No. PA-200-F, "U. S. Steel Homestead Works, 160-inch Plate Mill" HAER No. PA-200-G, "U. S. Steel Homestead Works, Main Roll Shop" HAER No. PA-200-H, "U. S. Steel Homestead Works, Structural Mill" HAER No. PA-200-I, "U. S. Steel Homestead Works, Machine Shop No. 1" HAER No. PA-200-J, "U. S. Steel Homestead Works, Machine Shop No. 2" HAER No. PA-200-K, "U. S. Steel Homestead Works, Press Shop No. 1" HAER No. PA-200-L, "U. S. Steel Homestead Works, Press Shop No. 2" HAER No. PA-200-M, "U. S. Steel Homestead Works, Harvey Shop" HAER No. PA-200-N, "U. S. Steel Homestead Works, Open Hearth Steelmaking Plant" HAER No.
PA-200-O, "U. S. Steel Homestead Works, Stainless Steel Processing Plant" HAER No. PA-200-P, "U. S. Steel Homestead Works, Auxiliary Buildings & Shops" HAER No. PA-301, "Mesta 160-Inch Plate Mill, Defense Plant Corporation, Homestead Works"
West Mifflin, Pennsylvania
West Mifflin is a borough in Allegheny County, United States, located southeast of downtown Pittsburgh. The population was 20,313 at the 2010 census, it is named after Thomas Mifflin, 1st Governor of Pennsylvania, signer of the United States Constitution, 1st Quartermaster General of the United States Army. Although the borough is residential, it is home to one of America's oldest traditional amusement parks, Kennywood Park. Other employers include advanced naval nuclear propulsion technology research and development facility, Bettis Atomic Power Laboratory. According to the United States Census Bureau, the borough has a total area of 14.4 square miles, of which 14.2 square miles is land and 0.3 square miles, or 1.80%, is water. The landscape is hilly and wooded, the borough's eastern boundary is contiguous with the Monongahela River three separate times. Much of the original landscape has been altered as a result of the historic dumping of steel mill byproducts such as slag and fly ash. Coal mining has affected the flow and water quality of small streams.
Land developers have produced more level ground by clean-filling ravines and other small parcels of land to improve the land usage. Toxic waste dump areas are monitored with water quality improvement with bioremediation implemented. West Mifflin operates its own sewage treatment facility; the Environmental Protection agency regulates 78 facilities for environmental compliance. Asbestos waste and radioactive waste and controls were addressed in 1991. West Mifflin has ten land borders, including the Pittsburgh neighborhoods of Lincoln Place and Hays as well as Munhall and Whitaker, to the north, Duquesne to the east, Dravosburg to the southeast, Jefferson Hills and Pleasant Hills to the south, Baldwin to the west and a short border with Clairton to the south. Three segments of West Mifflin run along the Monongahela River. Adjacent to these areas across the river are North Braddock, McKeesport and Glassport; as of the census of 2000, there were 22,464 people, 9,509 households, 6,475 families residing in the borough.
The population density was 1,586.2 people per square mile. There were 9,966 housing units at an average density of 703.7 per square mile. The racial makeup of the borough was 89.64% White, 8.85% African American, 0.12% Native American, 0.25% Asian, 0.06% Pacific Islander, 0.25% from other races, 0.84% from two or more races. Hispanic or Latino of any race were 0.57% of the population. There were 9,509 households, out of which 26.8% had children under the age of 18 living with them, 50.6% were married couples living together, 13.7% had a female householder with no husband present, 31.9% were non-families. 29.0% of all households were made up of individuals, 15.3% had someone living alone, 65 years of age or older. The average household size was 2.35 and the average family size was 2.89. In the borough the population was spread out, with 21.5% under the age of 18, 6.9% from 18 to 24, 26.2% from 25 to 44, 23.8% from 45 to 64, 21.6% who were 65 years of age or older. The median age was 42 years. For every 100 females, there were 89.4 males.
For every 100 females age 18 and over, there were 84.3 males. The median income for a household in the borough was $36,130, the median income for a family was $46,192. Males had a median income of $36,984 versus $26,529 for females; the per capita income for the borough was $18,140. About 8.8% of families and 10.2% of the population were below the poverty line, including 16.6% of those under age 18 and 9.1% of those age 65 or over. The unemployment rate is just over 6%. Eleven schools exist in West Mifflin: 4 private schools. West Mifflin public schools belong to one district-West Mifflin Area School District. School students in the neighboring boroughs of Whitaker and Duquesne attend school in the West Mifflin School District. There are 68 West Mifflin elementary schools, 4 West Mifflin middle schools, 2 West Mifflin high schools and 13 West Mifflin preschools. New England Elementary has been closed since June 2012. Prior to July 2016, Wilson Christian Academy existed at 1900 Clairton Road, it was merged into Cornerstone Christian Preparatory Academy, at that location.
West Mifflin school administrators' use of school credit cards for meals has been called into question. The West Mifflin School District charges tuition for nearby Duquesne students to attend. All-State Career School has a campus in West Mifflin. Class A CDL licenses have been in-demand in the area with the rise of fracking. Community College of Allegheny County has its South Campus in the borough at 1750 Clairton Road. D. R. Connors, Westinghouse Electric Corporation, Bettis Atomic Power Laboratory, West Mifflin, letter to R. L Pearson, Oak Ridge National Laboratory, Oak Ridge, Tennessee, "Update of Idaho Naval Reactor Facilities Miscellaneous Waste Inventory for the 1992 Integrated Data Base Report," dated May 5, 1992. Borough of West Mifflin official website West Mifflin Borough on Facebook West Mifflin Borough Recreation official website West Mifflin Borough Recreation on Facebook West Mifflin Borough Police Department official website West Mifflin Borough Police Department on Facebook West Mifflin Community Website History of West Mifflin West Mifflin Area School District West Mifflin Sanitary Sewer Municipal Authority
Open hearth furnace
Open hearth furnaces are one of a number of kinds of furnace where excess carbon and other impurities are burnt out of pig iron to produce steel. Since steel is difficult to manufacture due to its high melting point, normal fuels and furnaces were insufficient and the open hearth furnace was developed to overcome this difficulty. Compared to Bessemer steel, which it displaced, its main advantages were that it did not expose the steel to excessive nitrogen, was easier to control, it permitted the melting and refining of large amounts of scrap iron and steel; the open hearth furnace was first developed by German-born engineer Carl Wilhelm Siemens. In 1865, the French engineer Pierre-Émile Martin took out a license from Siemens and first applied his regenerative furnace for making steel, their process was known as the Siemens–Martin process, the furnace as an "open-hearth" furnace. Most open hearth furnaces were closed by the early 1990s, not least because of their slow operation, being replaced by the basic oxygen furnace or electric arc furnace.
Whereas earliest witness of open hearth steelmaking about 2000 years ago was found in the culture of the Haya people in present day Tanzania, in Europe in the Catalan forge, invented in Spain in the 8th century, it is usual to confine the term to certain 19th-century and steelmaking processes, thus excluding bloomeries, finery forges, puddling furnaces from its application. The open hearth process is a batch process and a batch is called a "heat"; the furnace is first inspected for possible damage. Once it is ready or repaired, it is charged with light scrap, such as sheet metal, shredded vehicles or waste metal; the furnace is heated using burning gas. Once it has melted, heavy scrap, such as building, construction or steel milling scrap is added, together with pig iron from blast furnaces. Once all the steel has melted, slag forming agents, such as limestone, are added; the oxygen in iron oxide and other impurities decarburize the pig iron by burning excess carbon away, forming steel. To increase the oxygen contents of the heat, iron ore can be added to the heat.
The process is far slower than that of Bessemer converter and thus easier to control and sample for quality assessment. Preparing a heat takes eight to eight and half hours to complete into steel; as the process is slow, it is not necessary to burn all the carbon away as in Bessemer process, but the process can be terminated at any given point when desired carbon contents has been achieved. The furnace is tapped the same way. Once all the steel has been tapped, the slag is skimmed away; the raw steel may be cast into ingots. The regenerators are the distinctive feature of the furnace and consist of fire-brick flues filled with bricks set on edge and arranged in such a way as to have a great number of small passages between them; the bricks absorb most of the heat from the outgoing waste gases and return it to the incoming cold gases for combustion. Sir Carl Wilhelm Siemens developed the Siemens regenerative furnace in the 1850s, claimed in 1857 to be recovering enough heat to save 70–80% of the fuel.
This furnace operates at a high temperature by using regenerative preheating of fuel and air for combustion. In regenerative preheating, the exhaust gases from the furnace are pumped into a chamber containing bricks, where heat is transferred from the gases to the bricks; the flow of the furnace is reversed so that fuel and air pass through the chamber and are heated by the bricks. Through this method, an open-hearth furnace can reach temperatures high enough to melt steel, but Siemens did not use it for that. In 1865, the French engineer Pierre-Émile Martin took out a license from Siemens and first applied his regenerative furnace for making steel; the most appealing characteristic of the Siemens regenerative furnace is the rapid production of large quantities of basic steel, used for example to construct high-rise buildings. The usual size of furnaces is 50 to 100 tons, but for some special processes they may have a capacity of 250 or 500 tons; the Siemens–Martin process complemented rather than replaced the Bessemer process.
It is slower and thus easier to control. It permits the melting and refining of large amounts of scrap steel, further lowering steel production costs and recycling an otherwise troublesome waste material, its worst drawback is the fact that refining a charge takes several hours. This was an advantage in the early 20th century, as it gave plant chemists time to analyze the steel and decide how much longer to refine it, but by about 1975, electronic instruments such as atomic absorption spectrophotometers had made analysis of the steel much easier and faster. The work environment around an open hearth furnace is said to be dangerous, although that may be more true of the environment around a basic oxygen or electric arc furnace. Basic oxygen steelmaking replaced the open hearth furnace, it superseded both the Bessemer process and Siemens–Martin process in Western Europe by the 1950s and in Eastern Europe by the 1980s. The open hearth steelmaking had superseded Bessemer process in UK by 1900, but elsewhere in Europe in Germany, the Bessemer and Thomas processes were used until the late 1960s when they were superseded by basic oxygen steelmaking.
The last open hearth furnace in the former East Germany was stopped in 1993. In the US, steel production using the Bessemer process ended in 1968 and the open hearth furnaces had stopped by 1992. In Hunedoara steel works, Romania the l