Scrap consists of recyclable materials, usually metals, left over from product manufacturing and consumption, such as parts of vehicles, building supplies, and surplus materials. Unlike waste , scrap can have monetary value , especially recovered metals , and non-metallic materials are also recovered for recycling. Once collected, the materials are sorted into types – typically metal scrap will be crushed, shredded, and sorted using mechanical processes.
77-559: Stal means steel in many Slavic languages. Stål is a name of Swedish origin. It may refer to: Steel Steel is an alloy of iron and carbon with improved strength and fracture resistance compared to other forms of iron. Because of its high tensile strength and low cost, steel is one of the most commonly manufactured materials in the world. Steel is used in buildings, as concrete reinforcing rods, in bridges, infrastructure, tools, ships, trains, cars, bicycles, machines, electrical appliances, furniture, and weapons. Iron
154-412: A BOS process is manufactured in one-twelfth the time. Today, electric arc furnaces (EAF) are a common method of reprocessing scrap metal to create new steel. They can also be used for converting pig iron to steel, but they use a lot of electrical energy (about 440 kWh per metric ton), and are thus generally only economical when there is a plentiful supply of cheap electricity. The steel industry
231-782: A Swedish government body responsible for geological survey of bedrock, soil and groundwater. Great potential exists in the scrap metal industry for accidents in which a hazardous material present in scrap causes death, injury, or environmental damage. A classic example is radioactivity in scrap ; the Goiânia accident and the Mayapuri radiological accident were incidents involving radioactive materials. Toxic materials such as asbestos , and toxic metals such as beryllium , cadmium , lead and mercury may pose dangers to personnel, as well as contaminating materials intended for metal smelters . Many specialized tools used in scrapyards are hazardous, such as
308-531: A brittle alloy commonly called pig iron . Alloy steel is steel to which other alloying elements have been intentionally added to modify the characteristics of steel. Common alloying elements include: manganese , nickel , chromium , molybdenum , boron , titanium , vanadium , tungsten , cobalt , and niobium . Additional elements, most frequently considered undesirable, are also important in steel: phosphorus , sulphur , silicon , and traces of oxygen , nitrogen , and copper . Plain carbon-iron alloys with
385-684: A carbon-intermediate steel by the 1st century AD. There is evidence that carbon steel was made in Western Tanzania by the ancestors of the Haya people as early as 2,000 years ago by a complex process of "pre-heating" allowing temperatures inside a furnace to reach 1300 to 1400 °C. Evidence of the earliest production of high carbon steel in South Asia is found in Kodumanal in Tamil Nadu ,
462-444: A change of volume. In this case, expansion occurs. Internal stresses from this expansion generally take the form of compression on the crystals of martensite and tension on the remaining ferrite, with a fair amount of shear on both constituents. If quenching is done improperly, the internal stresses can cause a part to shatter as it cools. At the very least, they cause internal work hardening and other microscopic imperfections. It
539-428: A ferrite BCC crystal form, but at higher carbon content it takes a body-centred tetragonal (BCT) structure. There is no thermal activation energy for the transformation from austenite to martensite. There is no compositional change so the atoms generally retain their same neighbours. Martensite has a lower density (it expands during the cooling) than does austenite, so that the transformation between them results in
616-583: A hard oxide forms on the metal surface; this is known as stainless steel . Tungsten slows the formation of cementite , keeping carbon in the iron matrix and allowing martensite to preferentially form at slower quench rates, resulting in high-speed steel . The addition of lead and sulphur decrease grain size, thereby making the steel easier to turn , but also more brittle and prone to corrosion. Such alloys are nevertheless frequently used for components such as nuts, bolts, and washers in applications where toughness and corrosion resistance are not paramount. For
693-445: A hard but brittle martensitic structure. The steel is then tempered, which is just a specialized type of annealing, to reduce brittleness. In this application the annealing (tempering) process transforms some of the martensite into cementite, or spheroidite and hence it reduces the internal stresses and defects. The result is a more ductile and fracture-resistant steel. When iron is smelted from its ore, it contains more carbon than
770-434: A higher than 2.1% carbon content are known as cast iron . With modern steelmaking techniques such as powder metal forming, it is possible to make very high-carbon (and other alloy material) steels, but such are not common. Cast iron is not malleable even when hot, but it can be formed by casting as it has a lower melting point than steel and good castability properties. Certain compositions of cast iron, while retaining
847-402: A magnet. Some cheaper grades of stainless steel are magnetic, other grades are not. These items are higher priced commodities for metal recycling and are important to separate when recycling them. The prices of non-ferrous metals also tend to fluctuate more than ferrous metals so it is important for recyclers to pay attention to these sources and the overall markets. This term is used to describe
SECTION 10
#1733086019898924-412: A narrow range of concentrations of mixtures of carbon and iron that make steel, several different metallurgical structures, with very different properties can form. Understanding such properties is essential to making quality steel. At room temperature , the most stable form of pure iron is the body-centred cubic (BCC) structure called alpha iron or α-iron. It is a fairly soft metal that can dissolve only
1001-534: A small concentration of carbon, no more than 0.005% at 0 °C (32 °F) and 0.021 wt% at 723 °C (1,333 °F). The inclusion of carbon in alpha iron is called ferrite . At 910 °C, pure iron transforms into a face-centred cubic (FCC) structure, called gamma iron or γ-iron. The inclusion of carbon in gamma iron is called austenite. The more open FCC structure of austenite can dissolve considerably more carbon, as much as 2.1%, (38 times that of ferrite) carbon at 1,148 °C (2,098 °F), which reflects
1078-448: A steel's final rolling, it is heat treated for strength; however, this is relatively rare. Steel was known in antiquity and was produced in bloomeries and crucibles . The earliest known production of steel is seen in pieces of ironware excavated from an archaeological site in Anatolia ( Kaman-Kalehöyük ) which are nearly 4,000 years old, dating from 1800 BC. Wootz steel
1155-477: A subsequent step. Other materials are often added to the iron/carbon mixture to produce steel with the desired properties. Nickel and manganese in steel add to its tensile strength and make the austenite form of the iron-carbon solution more stable, chromium increases hardness and melting temperature, and vanadium also increases hardness while making it less prone to metal fatigue . To inhibit corrosion, at least 11% chromium can be added to steel so that
1232-483: A time countries in south Asia carried out most shipbreaking, often using manual methods that were hazardous to workers and the environment. International regulations now dictate the treatment of old ships as sources of hazardous waste, so shipbreaking has returned to ports in more developed countries. In 2013, about 29 million tons of scrap steel were recovered from broken ships. Some of the scrap can be reheated and rolled to make products such as concrete reinforcing bars, or
1309-564: A wide range of informal roles such as waste pickers who help sorting through scrap. Scrap metal originates both in business and residential environments. Typically a "scrapper" will advertise their services to conveniently remove scrap metal for people who don't need it. Scrap is often taken to a wrecking yard (also known as a scrapyard, junkyard, or breaker's yard), where it is processed for later melting into new products. A wrecking yard, depending on its location, may allow customers to browse their lot and purchase items before they are sent to
1386-672: Is continuously cast into long slabs, cut and shaped into bars and extrusions and heat treated to produce a final product. Today, approximately 96% of steel is continuously cast, while only 4% is produced as ingots. The ingots are then heated in a soaking pit and hot rolled into slabs, billets , or blooms . Slabs are hot or cold rolled into sheet metal or plates. Billets are hot or cold rolled into bars, rods, and wire. Blooms are hot or cold rolled into structural steel , such as I-beams and rails . In modern steel mills these processes often occur in one assembly line , with ore coming in and finished steel products coming out. Sometimes after
1463-629: Is also very reusable: it is one of the world's most-recycled materials, with a recycling rate of over 60% globally . The noun steel originates from the Proto-Germanic adjective * * stahliją or * * stakhlijan 'made of steel', which is related to * * stahlaz or * * stahliją 'standing firm'. The carbon content of steel is between 0.02% and 2.14% by weight for plain carbon steel ( iron - carbon alloys ). Too little carbon content leaves (pure) iron quite soft, ductile, and weak. Carbon contents higher than those of steel make
1540-416: Is always the main element in steel, but many other elements may be present or added. Stainless steels , which are resistant to corrosion and oxidation , typically need an additional 11% chromium . Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic . The interaction of the allotropes of iron with
1617-403: Is common for quench cracks to form when steel is water quenched, although they may not always be visible. There are many types of heat treating processes available to steel. The most common are annealing , quenching , and tempering . Annealing is the process of heating the steel to a sufficiently high temperature to relieve local internal stresses. It does not create a general softening of
SECTION 20
#17330860198981694-403: Is desirable. To become steel, it must be reprocessed to reduce the carbon to the correct amount, at which point other elements can be added. In the past, steel facilities would cast the raw steel product into ingots which would be stored until use in further refinement processes that resulted in the finished product. In modern facilities, the initial product is close to the final composition and
1771-423: Is economically advantageous to do so. It is cheaper to recycle steel than to mine iron ore and manipulate it through the production process to form new steel. Steel does not lose any of its inherent physical properties during the recycling process, and has drastically reduced energy and material requirements compared with refinement from iron ore. The energy saved by recycling reduces the annual energy consumption of
1848-405: Is extracted from iron ore by removing the oxygen through its combination with a preferred chemical partner such as carbon which is then lost to the atmosphere as carbon dioxide. This process, known as smelting , was first applied to metals with lower melting points, such as tin , which melts at about 250 °C (482 °F), and copper , which melts at about 1,100 °C (2,010 °F), and
1925-408: Is heat treated to contain both a ferritic and martensitic microstructure to produce a formable, high strength steel. Transformation Induced Plasticity (TRIP) steel involves special alloying and heat treatments to stabilize amounts of austenite at room temperature in normally austenite-free low-alloy ferritic steels. By applying strain, the austenite undergoes a phase transition to martensite without
2002-454: Is important to making more money on scrap, tips like using a magnet to determine ferrous and non-ferrous materials can help recyclers make more money on their metal recycling. When a magnet sticks to the metal, it will be a ferrous material, like steel or iron. This is usually a less expensive item that is recycled but usually is recycled in larger quantities of thousands of pounds. Non-ferrous metals like copper, aluminum, and brass do not stick to
2079-687: Is often considered an indicator of economic progress, because of the critical role played by steel in infrastructural and overall economic development . In 1980, there were more than 500,000 U.S. steelworkers. By 2000, the number of steelworkers had fallen to 224,000. The economic boom in China and India caused a massive increase in the demand for steel. Between 2000 and 2005, world steel demand increased by 6%. Since 2000, several Indian and Chinese steel firms have expanded to meet demand, such as Tata Steel (which bought Corus Group in 2007), Baosteel Group and Shagang Group . As of 2017 , though, ArcelorMittal
2156-864: Is often used to make automotive fenders , tin cans , industrial drums , or any product with a large degree of cold working. EAF steelmaking uses almost 100% recycled steel. This steel contains greater concentrations of residual elements that cannot be removed through the application of oxygen and lime . It is used to make structural beams , plates , reinforcing bar , and other products that require little cold working. Downcycling of steel by hard-to-separate impurities such as copper or tin can only be prevented by well-aimed scrap selection or dilution by pure steel. Recycling one metric ton (1,000 kilograms ) of steel saves 1.1 metric tons of iron ore , 630 kilograms of coal , and 55 kilograms of limestone . The hulls of ships, with any usable equipment salvaged and removed, can be broken up to provide scrap steel. For
2233-544: Is one of the world's most-recycled materials, with a recycling rate of over 60% globally; in the United States alone, over 82,000,000 metric tons (81,000,000 long tons; 90,000,000 short tons) were recycled in the year 2008, for an overall recycling rate of 83%. As more steel is produced than is scrapped, the amount of recycled raw materials is about 40% of the total of steel produced - in 2016, 1,628,000,000 tonnes (1.602 × 10 long tons; 1.795 × 10 short tons) of crude steel
2310-529: Is the world's largest steel producer . In 2005, the British Geological Survey stated China was the top steel producer with about one-third of the world share; Japan , Russia , and the United States were second, third, and fourth, respectively, according to the survey. The large production capacity of steel results also in a significant amount of carbon dioxide emissions inherent related to
2387-631: The Golconda area in Andhra Pradesh and Karnataka , regions of India , as well as in Samanalawewa and Dehigaha Alakanda, regions of Sri Lanka . This came to be known as wootz steel , produced in South India by about the sixth century BC and exported globally. The steel technology existed prior to 326 BC in the region as they are mentioned in literature of Sangam Tamil , Arabic, and Latin as
Stal - Misplaced Pages Continue
2464-912: The alligator shear , which cuts metal using hydraulic force, compactors , scrap metal shredder , and vacuum . According to the WHO (2023), “When e-waste is treated using inferior activities, it can release as many as 1000 different chemical substances ... including harmful … “ The metal recycling industry encompasses a wide range of metals. The more frequently recycled metals are scrap steel, iron (ISS), lead , aluminum, copper, stainless steel, and zinc. There are two main categories of metals: ferrous and non-ferrous. Metals that contain iron in them are known as ferrous . Metals without iron are non-ferrous . Non-ferrous metals also include precious and exotic metals: OSHA guidelines should be followed when recycling any type of scrap metal to ensure safety. Ferrous metals are able to be recycled , with steel being one of
2541-586: The cementation process was described in a treatise published in Prague in 1574 and was in use in Nuremberg from 1601. A similar process for case hardening armour and files was described in a book published in Naples in 1589. The process was introduced to England in about 1614 and used to produce such steel by Sir Basil Brooke at Coalbrookdale during the 1610s. The raw material for this process were bars of iron. During
2618-419: The hardness , quenching behaviour , need for annealing , tempering behaviour , yield strength , and tensile strength of the resulting steel. The increase in steel's strength compared to pure iron is possible only by reducing iron's ductility. Steel was produced in bloomery furnaces for thousands of years, but its large-scale, industrial use began only after more efficient production methods were devised in
2695-511: The smelters , although many scrap yards that deal in large quantities of scrap usually do not, often selling entire units such as engines or machinery by weight with no regard to their functional status. Customers are typically required to supply all of their own tools and labor to extract parts, and some scrapyards may first require waiving liability for personal injury before entering. Many scrapyards also sell bulk metals ( stainless steel , etc.) by weight, often at prices substantially below
2772-445: The 17th century, it was realized that the best steel came from oregrounds iron of a region north of Stockholm , Sweden. This was still the usual raw material source in the 19th century, almost as long as the process was used. Crucible steel is steel that has been melted in a crucible rather than having been forged , with the result that it is more homogeneous. Most previous furnaces could not reach high enough temperatures to melt
2849-470: The 17th century, the first step in European steel production has been the smelting of iron ore into pig iron in a blast furnace . Originally employing charcoal, modern methods use coke , which has proven more economical. In these processes, pig iron made from raw iron ore was refined (fined) in a finery forge to produce bar iron , which was then used in steel-making. The production of steel by
2926-607: The 17th century, with the introduction of the blast furnace and production of crucible steel . This was followed by the Bessemer process in England in the mid-19th century, and then by the open-hearth furnace . With the invention of the Bessemer process, a new era of mass-produced steel began. Mild steel replaced wrought iron . The German states were the major steel producers in Europe in
3003-475: The 19th century. American steel production was centred in Pittsburgh , Bethlehem, Pennsylvania , and Cleveland until the late 20th century. Currently, world steel production is centered in China, which produced 54% of the world's steel in 2023. Further refinements in the process, such as basic oxygen steelmaking (BOS), largely replaced earlier methods by further lowering the cost of production and increasing
3080-600: The Arabs from Persia, who took it from India. It was originally created from several different materials including various trace elements , apparently ultimately from the writings of Zosimos of Panopolis . In 327 BC, Alexander the Great was rewarded by the defeated King Porus , not with gold or silver but with 30 pounds of steel. A recent study has speculated that carbon nanotubes were included in its structure, which might explain some of its legendary qualities, though, given
3157-463: The Linz-Donawitz process of basic oxygen steelmaking (BOS), developed in 1952, and other oxygen steel making methods. Basic oxygen steelmaking is superior to previous steelmaking methods because the oxygen pumped into the furnace limited impurities, primarily nitrogen, that previously had entered from the air used, and because, with respect to the open hearth process, the same quantity of steel from
Stal - Misplaced Pages Continue
3234-479: The US scrap price, which has become increasingly important to global export markets. Scrap yards directories are also used by recyclers to find facilities in the US and Canada, allowing users to get in contact with yards. With resources online for recyclers to look at for scrapping tips, like websites, blogs, and search engines, scrapping is often referred to as a hand and labor-intensive job. Taking apart and separating metals
3311-478: The addition of heat. Twinning Induced Plasticity (TWIP) steel uses a specific type of strain to increase the effectiveness of work hardening on the alloy. Ferrous metal recycling Metal recycling, especially of structural steel , ships , used manufactured goods, such as vehicles and white goods , is an industrial activity with complex networks of wrecking yards , sorting facilities, and recycling plants. The industry includes both formal organizations and
3388-401: The alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile , or soft and easily formed. In steel, small amounts of carbon, other elements, and inclusions within the iron act as hardening agents that prevent
3465-436: The austenite grain boundaries until the percentage of carbon in the grains has decreased to the eutectoid composition (0.8% carbon), at which point the pearlite structure forms. For steels that have less than 0.8% carbon (hypoeutectoid), ferrite will first form within the grains until the remaining composition rises to 0.8% of carbon, at which point the pearlite structure will form. No large inclusions of cementite will form at
3542-471: The austenite is for it to precipitate out of solution as cementite , leaving behind a surrounding phase of BCC iron called ferrite with a small percentage of carbon in solution. The two, cementite and ferrite, precipitate simultaneously producing a layered structure called pearlite , named for its resemblance to mother of pearl . In a hypereutectoid composition (greater than 0.8% carbon), the carbon will first precipitate out as large inclusions of cementite at
3619-494: The boundaries in hypoeutectoid steel. The above assumes that the cooling process is very slow, allowing enough time for the carbon to migrate. As the rate of cooling is increased the carbon will have less time to migrate to form carbide at the grain boundaries but will have increasingly large amounts of pearlite of a finer and finer structure within the grains; hence the carbide is more widely dispersed and acts to prevent slip of defects within those grains, resulting in hardening of
3696-455: The combination, bronze, which has a melting point lower than 1,083 °C (1,981 °F). In comparison, cast iron melts at about 1,375 °C (2,507 °F). Small quantities of iron were smelted in ancient times, in the solid-state, by heating the ore in a charcoal fire and then welding the clumps together with a hammer and in the process squeezing out the impurities. With care, the carbon content could be controlled by moving it around in
3773-426: The current steel consumption for each industry with the amount of recycled steel being produced (the late 2000s recession and the associated sharp decline in automobile production in the US explains the over-100% calculation). A typical appliance is about 75% steel by weight and automobiles are about 65% steel and iron. The steel industry has been actively recycling for more than 150 years, in large part because it
3850-448: The economies of melting and casting, can be heat treated after casting to make malleable iron or ductile iron objects. Steel is distinguishable from wrought iron (now largely obsolete), which may contain a small amount of carbon but large amounts of slag . Iron is commonly found in the Earth's crust in the form of an ore , usually an iron oxide, such as magnetite or hematite . Iron
3927-625: The finest steel in the world exported to the Roman, Egyptian, Chinese and Arab worlds at that time – what they called Seric Iron . A 200 BC Tamil trade guild in Tissamaharama , in the South East of Sri Lanka, brought with them some of the oldest iron and steel artifacts and production processes to the island from the classical period . The Chinese and locals in Anuradhapura , Sri Lanka had also adopted
SECTION 50
#17330860198984004-573: The fire. Unlike copper and tin, liquid or solid iron dissolves carbon quite readily. All of these temperatures could be reached with ancient methods used since the Bronze Age . Since the oxidation rate of iron increases rapidly beyond 800 °C (1,470 °F), it is important that smelting take place in a low-oxygen environment. Smelting, using carbon to reduce iron oxides, results in an alloy ( pig iron ) that retains too much carbon to be called steel. The excess carbon and other impurities are removed in
4081-503: The form of charcoal) in a crucible, was produced in Merv by the 9th to 10th century AD. In the 11th century, there is evidence of the production of steel in Song China using two techniques: a "berganesque" method that produced inferior, inhomogeneous steel, and a precursor to the modern Bessemer process that used partial decarburization via repeated forging under a cold blast . Since
4158-599: The hardenability of thick sections. High strength low alloy steel has small additions (usually < 2% by weight) of other elements, typically 1.5% manganese, to provide additional strength for a modest price increase. Recent corporate average fuel economy (CAFE) regulations have given rise to a new variety of steel known as Advanced High Strength Steel (AHSS). This material is both strong and ductile so that vehicle structures can maintain their current safety levels while using less material. There are several commercially available grades of AHSS, such as dual-phase steel , which
4235-900: The industry by about 75%, which is enough to power eighteen million homes for one year. According to the International Resource Panel 's Metal Stocks in Society report , the per capita stock of steel in use in Australia, Canada, the European Union EU15, Norway, Switzerland, Japan, New Zealand, and the US combined is 7,085 kilograms (15,620 lb) (about 860 million people in 2005). Basic oxygen steelmaking (BOS) uses 25–35% recycled steel to make new steel. BOS steel usually contains lower concentrations of residual elements such as copper , nickel , and molybdenum , and is, therefore more malleable than electric arc furnace (EAF) steel, and
4312-439: The main production route. At the end of 2008, the steel industry faced a sharp downturn that led to many cut-backs. In 2021, it was estimated that around 7% of the global greenhouse gas emissions resulted from the steel industry. Reduction of these emissions are expected to come from a shift in the main production route using cokes, more recycling of steel and the application of carbon capture and storage technology. Steel
4389-450: The most part, however, p-block elements such as sulphur, nitrogen , phosphorus , and lead are considered contaminants that make steel more brittle and are therefore removed from steel during the melting processing. The density of steel varies based on the alloying constituents but usually ranges between 7,750 and 8,050 kg/m (484 and 503 lb/cu ft), or 7.75 and 8.05 g/cm (4.48 and 4.65 oz/cu in). Even in
4466-426: The most recycled materials in the world. Ferrous metals contain an appreciable percentage of iron and the addition of carbon and other substances creates steel . In the United States, steel containers, cans, automobiles, appliances, and construction materials contribute the greatest weight of recycled materials. For example, in 2008, more than 97% of structural steel and 106% of automobiles were recycled, comparing
4543-446: The movement of dislocations . The carbon in typical steel alloys may contribute up to 2.14% of its weight. Varying the amount of carbon and many other alloying elements, as well as controlling their chemical and physical makeup in the final steel (either as solute elements, or as precipitated phases), impedes the movement of the dislocations that make pure iron ductile, and thus controls and enhances its qualities. These qualities include
4620-469: The number of thefts increasing as prices rise. Manhole covers have also been stolen. In the 1970s, the term "newsjacking" was coined to describe the theft of newspapers for sale to scrap dealers. Scrap prices may vary markedly over time and in different locations. Prices are often negotiated between buyers and sellers directly or indirectly over the Internet. Prices displayed as the market prices are not
4697-441: The prices that recyclers will see at the scrap yards. Other prices are ranges or older and not updated frequently. Some scrap yards' websites have updated scrap prices. In the US, scrap prices are reported in a handful of publications, including American Metal Market , based on confirmed sales as well as reference sites such as Scrap Metal Prices and Auctions. Non-US domiciled publications, such as The Steel Index , also report on
SECTION 60
#17330860198984774-449: The product but only locally relieves strains and stresses locked up within the material. Annealing goes through three phases: recovery , recrystallization , and grain growth . The temperature required to anneal a particular steel depends on the type of annealing to be achieved and the alloying constituents. Quenching involves heating the steel to create the austenite phase then quenching it in water or oil . This rapid cooling results in
4851-741: The production methods of creating wootz steel from the Chera Dynasty Tamils of South India by the 5th century AD. In Sri Lanka, this early steel-making method employed a unique wind furnace, driven by the monsoon winds, capable of producing high-carbon steel. Since the technology was acquired from the Tamilians from South India, the origin of steel technology in India can be conservatively estimated at 400–500 BC. The manufacture of wootz steel and Damascus steel , famous for its durability and ability to hold an edge, may have been taken by
4928-426: The quality of the final product. Today more than 1.6 billion tons of steel is produced annually. Modern steel is generally identified by various grades defined by assorted standards organizations . The modern steel industry is one of the largest manufacturing industries in the world, but also one of the most energy and greenhouse gas emission intense industries, contributing 8% of global emissions. However, steel
5005-615: The recovery of "dormant" materials that once served a purpose in society but have become disused since. For example, large amounts of metal are buried underground as part of the provision of basic services including telecoms. Infrastructure, buildings and equipment stored or lying dormant in this way accounted for 28% of Sweden's copper use in 2021. In the same period, one sixth of the cables installed in Sweden's telecoms came from harvesting via urban mining. In particular this involved copper, aluminium, iron and steel. Figures for this are issued by SGU,
5082-410: The retail purchasing costs of similar pieces. A scrap metal shredder is often used to recycle items containing a variety of other materials in combination with steel. Examples are automobiles and white goods such as refrigerators, stoves, clothes washers, etc. These items are labor-intensive to manually sort things like plastic, copper, aluminum, and brass. By shredding it into relatively small pieces,
5159-597: The same scrap based on what the item does, regardless of what it weighs. Typically, if a wrecker cannot sell something above the value of the metal in it, they would then take it to the scrapyard and sell it by weight. Equipment containing parts of various metals can often be purchased at a price below that of either of the metals, due to saving the scrapyard the labor of separating the metals before shipping them to be recycled. Thieves sometimes sell stolen items to scrapyards. Copper pipes and wiring, bronze monuments and aluminium siding have all been targets of metal theft , with
5236-703: The scrap may be melted to make new steel. The scrap industry was valued at more than $ 90 billion in 2012, up from $ 54 billion in 2009 balance of trade , exporting $ 28 billion in scrap commodities to 160 countries. Since 2010, the industry has added more than 15,000 jobs and supports 463,000 workers, both directly and indirectly. In addition, it generates more than $ 10 billion in revenue for federal, state, and local governments. Scrap recycling also helps reduce greenhouse gas emissions and conserves energy and natural resources. For example, scrap recycling diverts 135 million short tons (121,000,000 long tons; 122,000,000 t) of materials away from landfills . Recycled scrap
5313-425: The steel can easily be separated out magnetically. The non-ferrous waste stream requires other techniques to sort. In contrast to wrecking yards, scrapyards typically sell everything by weight, instead of by item. To the scrapyard, the primary value of the scrap is what the smelter will give them for it, rather than the value of whatever shape the metal may be in. An auto wrecker, on the other hand, would price exactly
5390-401: The steel. At the very high cooling rates produced by quenching, the carbon has no time to migrate but is locked within the face-centred austenite and forms martensite . Martensite is a highly strained and stressed, supersaturated form of carbon and iron and is exceedingly hard but brittle. Depending on the carbon content, the martensitic phase takes different forms. Below 0.2% carbon, it takes on
5467-556: The steel. The early modern crucible steel industry resulted from the invention of Benjamin Huntsman in the 1740s. Blister steel (made as above) was melted in a crucible or in a furnace, and cast (usually) into ingots. The modern era in steelmaking began with the introduction of Henry Bessemer 's process in 1855, the raw material for which was pig iron. His method let him produce steel in large quantities cheaply, thus mild steel came to be used for most purposes for which wrought iron
5544-555: The technology of that time, such qualities were produced by chance rather than by design. Natural wind was used where the soil containing iron was heated by the use of wood. The ancient Sinhalese managed to extract a ton of steel for every 2 tons of soil, a remarkable feat at the time. One such furnace was found in Samanalawewa and archaeologists were able to produce steel as the ancients did. Crucible steel , formed by slowly heating and cooling pure iron and carbon (typically in
5621-522: The upper carbon content of steel, beyond which is cast iron. When carbon moves out of solution with iron, it forms a very hard, but brittle material called cementite (Fe 3 C). When steels with exactly 0.8% carbon (known as a eutectoid steel), are cooled, the austenitic phase (FCC) of the mixture attempts to revert to the ferrite phase (BCC). The carbon no longer fits within the FCC austenite structure, resulting in an excess of carbon. One way for carbon to leave
5698-697: Was developed in Southern India and Sri Lanka in the 1st millennium BCE. Metal production sites in Sri Lanka employed wind furnaces driven by the monsoon winds, capable of producing high-carbon steel. Large-scale wootz steel production in India using crucibles occurred by the sixth century BC, the pioneering precursor to modern steel production and metallurgy. High-carbon steel was produced in Britain at Broxmouth Hillfort from 490–375 BC, and ultrahigh-carbon steel
5775-502: Was formerly used. The Gilchrist-Thomas process (or basic Bessemer process ) was an improvement to the Bessemer process, made by lining the converter with a basic material to remove phosphorus. Another 19th-century steelmaking process was the Siemens-Martin process , which complemented the Bessemer process. It consisted of co-melting bar iron (or steel scrap) with pig iron. These methods of steel production were rendered obsolete by
5852-438: Was produced globally, with 630,000,000 tonnes (620,000,000 long tons; 690,000,000 short tons) recycled. Modern steels are made with varying combinations of alloy metals to fulfil many purposes. Carbon steel , composed simply of iron and carbon, accounts for 90% of steel production. Low alloy steel is alloyed with other elements, usually molybdenum , manganese, chromium, or nickel, in amounts of up to 10% by weight to improve
5929-729: Was produced in the Netherlands from the 2nd-4th centuries AD. The Roman author Horace identifies steel weapons such as the falcata in the Iberian Peninsula , while Noric steel was used by the Roman military . The Chinese of the Warring States period (403–221 BC) had quench-hardened steel, while Chinese of the Han dynasty (202 BC—AD 220) created steel by melting together wrought iron with cast iron, thus producing
#897102