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109-501: The Korean Bell of Friendship (more commonly called Korean Friendship Bell ) is a massive bronze bell housed in a stone pavilion located in Angel's Gate Park, situated in the San Pedro neighborhood of Los Angeles, California . Positioned at the intersection of Gaffey and 37th Streets, this section of the park is also referred to as the "Korean–American Peace Park" and occupies a portion of

218-593: A Vinča culture site in Pločnik ( Serbia ), and believed to have been smelted from a natural tin-copper ore, stannite . Other early examples date to the late 4th millennium BC in Egypt , Susa (Iran) and some ancient sites in China, Luristan (Iran), Tepe Sialk (Iran), Mundigak (Afghanistan), and Mesopotamia (Iraq). Tin bronze was superior to arsenic bronze in that the alloying process could be more easily controlled, and

327-461: A compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation. Sometimes alloys may exhibit marked differences in behavior even when small amounts of one element are present. For example, impurities in semiconducting ferromagnetic alloys lead to different properties, as first predicted by White, Hogan, Suhl, Tian Abrie and Nakamura. Unlike pure metals, most alloys do not have

436-518: A copper oxide (eventually becoming copper carbonate) layer is formed, the underlying metal is protected from further corrosion . This can be seen on statues from the Hellenistic period. If copper chlorides are formed, a corrosion-mode called " bronze disease " will eventually completely destroy it. Bronze, or bronze-like alloys and mixtures, were used for coins over a longer period. Bronze was especially suitable for use in boat and ship fittings prior to

545-466: A gaseous state, such as found in a blast furnace to make pig iron (liquid-gas), nitriding , carbonitriding or other forms of case hardening (solid-gas), or the cementation process used to make blister steel (solid-gas). It may also be done with one, more, or all of the constituents in the solid state, such as found in ancient methods of pattern welding (solid-solid), shear steel (solid-solid), or crucible steel production (solid-liquid), mixing

654-540: A hard bronze-head, but a softer bronze-tang, combining the alloys to prevent both dulling and breaking during use. Mercury has been smelted from cinnabar for thousands of years. Mercury dissolves many metals, such as gold, silver, and tin, to form amalgams (an alloy in a soft paste or liquid form at ambient temperature). Amalgams have been used since 200 BC in China for gilding objects such as armor and mirrors with precious metals. The ancient Romans often used mercury-tin amalgams for gilding their armor. The amalgam

763-503: A height of 12 ft (3.63 m). The exterior surface is richly decorated in relief , featuring four pairs of figures. Each pair includes a "Goddess of Liberty" (bearing some resemblance to the Statue of Liberty ) and a Seonnyeo , or Korean spirit figure, holding the South Korean national symbol: a Taegeuk symbol, a branch of rose of Sharon , a branch of laurel , and a dove. The bell

872-655: A major influence on the development of cultures. In Europe, a major source of tin was the British deposits of ore in Cornwall , which were traded as far as Phoenicia in the eastern Mediterranean . In many parts of the world, large hoards of bronze artifacts are found, suggesting that bronze also represented a store of value and an indicator of social status. In Europe, large hoards of bronze tools, typically socketed axes (illustrated above), are found, which mostly show no signs of wear. With Chinese ritual bronzes , which are documented in

981-446: A molten metal is mixed with another substance, there are two mechanisms that can cause an alloy to form, called atom exchange and the interstitial mechanism . The relative size of each element in the mix plays a primary role in determining which mechanism will occur. When the atoms are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of

1090-433: A molten metal may not always mix with another element. For example, pure iron is almost completely insoluble with copper. Even when the constituents are soluble, each will usually have a saturation point , beyond which no more of the constituent can be added. Iron, for example, can hold a maximum of 6.67% carbon. Although the elements of an alloy usually must be soluble in the liquid state, they may not always be soluble in

1199-455: A more concentrated form of iron carbide (Fe 3 C) in the spaces between the pure iron crystals. The steel then becomes heterogeneous, as it is formed of two phases, the iron-carbon phase called cementite (or carbide ), and pure iron ferrite . Such a heat treatment produces a steel that is rather soft. If the steel is cooled quickly, however, the carbon atoms will not have time to diffuse and precipitate out as carbide, but will be trapped within

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1308-405: A pioneer in steel metallurgy, took an interest and produced a steel alloy containing around 12% manganese. Called mangalloy , it exhibited extreme hardness and toughness, becoming the first commercially viable alloy-steel. Afterward, he created silicon steel, launching the search for other possible alloys of steel. Robert Forester Mushet found that by adding tungsten to steel it could produce

1417-599: A range of alloys that may be harder than copper alone, or have other useful properties, such as strength , ductility , or machinability . The archaeological period in which bronze was the hardest metal in widespread use is known as the Bronze Age . The beginning of the Bronze Age in western Eurasia and India is conventionally dated to the mid-4th millennium BC (~3500 BC), and to the early 2nd millennium BC in China; elsewhere it gradually spread across regions. The Bronze Age

1526-546: A sharper edge longer. Bronze was still used during the Iron Age, and has continued in use for many purposes to the modern day. There are many different bronze alloys, but typically modern bronze is 88% copper and 12% tin. Alpha bronze consists of the alpha solid solution of tin in copper. Alpha bronze alloys of 4–5% tin are used to make coins, springs, turbines and blades. Historical "bronzes" are highly variable in composition, as most metalworkers probably used whatever scrap

1635-429: A single melting point , but a melting range during which the material is a mixture of solid and liquid phases (a slush). The temperature at which melting begins is called the solidus , and the temperature when melting is just complete is called the liquidus . For many alloys there is a particular alloy proportion (in some cases more than one), called either a eutectic mixture or a peritectic composition, which gives

1744-420: A very hard edge that would resist losing its hardness at high temperatures. "R. Mushet's special steel" (RMS) became the first high-speed steel . Mushet's steel was quickly replaced by tungsten carbide steel, developed by Taylor and White in 1900, in which they doubled the tungsten content and added small amounts of chromium and vanadium, producing a superior steel for use in lathes and machining tools. In 1903,

1853-480: A way to harden aluminium alloys for use in machine-gun cartridge cases. Knowing that aluminium-copper alloys were heat-treatable to some degree, Wilm tried quenching a ternary alloy of aluminium, copper, and the addition of magnesium, but was initially disappointed with the results. However, when Wilm retested it the next day he discovered that the alloy increased in hardness when left to age at room temperature, and far exceeded his expectations. Although an explanation for

1962-498: Is traditional . It is axially symmetric, consisting of a hipped (a.k.a. "pyramidal") roof supported by twelve columns representing the Korean zodiac , each column guarded by a carved animal. The color patterning along the bell's pavilion is known in Korean as dancheong . In 2013, the bell received a full restoration to remove accumulated rust and graffiti tagging, and access to the bell and

2071-416: Is a better conductor of heat and electricity than most steels. The cost of copper-base alloys is generally higher than that of steels but lower than that of nickel -base alloys. Bronzes are typically ductile alloys, considerably less brittle than cast iron. Copper and its alloys have a huge variety of uses that reflect their versatile physical, mechanical, and chemical properties . Some common examples are

2180-576: Is a metal. This is usually called the primary metal or the base metal, and the name of this metal may also be the name of the alloy. The other constituents may or may not be metals but, when mixed with the molten base, they will be soluble and dissolve into the mixture. The mechanical properties of alloys will often be quite different from those of its individual constituents. A metal that is normally very soft ( malleable ), such as aluminium , can be altered by alloying it with another soft metal, such as copper . Although both metals are very soft and ductile ,

2289-761: Is extremely slow thus the penetration was not very deep, so the alloy was not homogeneous. In 1740, Benjamin Huntsman began melting blister steel in a crucible to even out the carbon content, creating the first process for the mass production of tool steel . Huntsman's process was used for manufacturing tool steel until the early 1900s. The introduction of the blast furnace to Europe in the Middle Ages meant that people could produce pig iron in much higher volumes than wrought iron. Because pig iron could be melted, people began to develop processes to reduce carbon in liquid pig iron to create steel. Puddling had been used in China since

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2398-513: Is likely that 'nehoshet' refers to copper and its alloys with tin, now called bronze. In the King James Version, there is no use of the word 'bronze' and 'nehoshet' was translated as 'brass'. Modern translations use 'bronze'. Bronze (nehoshet) was used widely in the Tabernacle for items such as the bronze altar (Exodus Ch.27), bronze laver (Exodus Ch.30), utensils, and mirror (Exodus Ch.38). It

2507-613: Is noteworthy that the Emille Bell is the largest bell ever cast in Korean history, and both the Emille Bell and the Korean Friendship Bell are among the largest bells in the world. The bell is made of over seventeen tons of copper and tin , with gold , nickel , lead , and phosphorus added to the alloy for tone quality . It has a circumference of 23.8 ft (7.25 m), diameter of 7 + 1 ⁄ 2  ft (2.3 m), average thickness of 8 in (200 mm), and

2616-400: Is performed by heating the base metal beyond its melting point and then dissolving the solutes into the molten liquid, which may be possible even if the melting point of the solute is far greater than that of the base. For example, in its liquid state, titanium is a very strong solvent capable of dissolving most metals and elements. In addition, it readily absorbs gases like oxygen and burns in

2725-471: Is prevented (forming martensite), most heat-treatable alloys are precipitation hardening alloys, that depend on the diffusion of alloying elements to achieve their strength. When heated to form a solution and then cooled quickly, these alloys become much softer than normal, during the diffusionless transformation, but then harden as they age. The solutes in these alloys will precipitate over time, forming intermetallic phases, which are difficult to discern from

2834-453: Is used to make hammers , mallets , wrenches and other durable tools to be used in explosive atmospheres or in the presence of flammable vapors. Bronze is used to make bronze wool for woodworking applications where steel wool would discolor oak . Phosphor bronze is used for ships' propellers, musical instruments, and electrical contacts. Bearings are often made of bronze for its friction properties. It can be impregnated with oil to make

2943-541: Is used to make the tone rings of many professional model banjos . The tone ring is a heavy (usually 3 lb; 1.4 kg) folded or arched metal ring attached to a thick wood rim, over which a skin, or most often, a plastic membrane (or head) is stretched – it is the bell bronze that gives the banjo a crisp powerful lower register and clear bell-like treble register. Bronze has also been used in coins; most "copper" coins are actually bronze, with about 4 percent tin and 1 percent zinc. As with coins, bronze has been used in

3052-645: The COVID-19 pandemic in Los Angeles , reopening in May 2021. The Korean Friendship Bell is featured in films, television shows, and video games including: Bronze Bronze is an alloy consisting primarily of copper , commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium , manganese , nickel , or zinc ) and sometimes non-metals, such as phosphorus , or metalloids , such as arsenic or silicon . These additions produce

3161-547: The Etruscans were making bronze mirrors in the sixth century BC, and Greek and Roman mirrors followed the same pattern. Although other materials such as speculum metal had come into use, and Western glass mirrors had largely taken over, bronze mirrors were still being made in Japan and elsewhere in the eighteenth century, and are still made on a small scale in Kerala , India. Bronze is

3270-503: The Golden Age , when men lived among the gods; the Silver age , where youth lasted a hundred years; and the Bronze Age , the era of heroes. It was first adopted for a sports event at the 1904 Summer Olympics . At the 1896 event, silver was awarded to winners and bronze to runners-up, while at 1900 other prizes were given rather than medals. Bronze is the normal material for the related form of

3379-743: The Kingdom of Benin ; in Europe, Grecian bronzes typically of figures from Greek mythology ; in east Asia , Chinese ritual bronzes of the Shang and Zhou dynasty —more often ceremonial vessels but including some figurine examples. Bronze continues into modern times as one of the materials of choice for monumental statuary. Tiffany Glass Studios, made famous by Louis C. Tiffany commonly referred to his product as favrile glass or " Tiffany glass ," and used bronze in their artisan work for his Tiffany lamps . The largest and most ornate bronze fountain known to be cast in

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3488-560: The Wright brothers used a chromium-nickel steel to make the crankshaft for their airplane engine, while in 1908 Henry Ford began using vanadium steels for parts like crankshafts and valves in his Model T Ford , due to their higher strength and resistance to high temperatures. In 1912, the Krupp Ironworks in Germany developed a rust-resistant steel by adding 21% chromium and 7% nickel, producing

3597-514: The bloomery process , it produced very soft but ductile wrought iron . By 800 BC, iron-making technology had spread to Europe, arriving in Japan around 700 AD. Pig iron , a very hard but brittle alloy of iron and carbon, was being produced in China as early as 1200 BC, but did not arrive in Europe until the Middle Ages. Pig iron has a lower melting point than iron, and was used for making cast-iron . However, these metals found little practical use until

3706-539: The plaquette , normally a rectangular work of art with a scene in relief , for a collectors' market. Bronze is also associated with eighth wedding anniversaries. There are over 125 references to bronze ('nehoshet'), which appears to be the Hebrew word used for copper and any of its alloys. However, the Old Testament era Hebrews are not thought to have had the capability to manufacture zinc (needed to make brass) and so it

3815-408: The solid state. If the metals remain soluble when solid, the alloy forms a solid solution , becoming a homogeneous structure consisting of identical crystals, called a phase . If as the mixture cools the constituents become insoluble, they may separate to form two or more different types of crystals, creating a heterogeneous microstructure of different phases, some with more of one constituent than

3924-623: The 12th-century Romanesque Baptismal font at St Bartholomew's Church, Liège is sometimes described as bronze and sometimes as brass . In the Bronze Age, two forms of bronze were commonly used: "classic bronze", about 10% tin, was used in casting; and "mild bronze", about 6% tin, was hammered from ingots to make sheets. Bladed weapons were mostly cast from classic bronze, while helmets and armor were hammered from mild bronze. Modern commercial bronze (90% copper and 10% zinc) and architectural bronze (57% copper, 3% lead , 40% zinc) are more properly regarded as brass alloys because they contain zinc as

4033-670: The Mediterranean, so it was often valued higher than gold. To make jewellery, cutlery, or other objects from tin, workers usually alloyed it with other metals to increase strength and hardness. These metals were typically lead , antimony , bismuth or copper. These solutes were sometimes added individually in varying amounts, or added together, making a wide variety of objects, ranging from practical items such as dishes, surgical tools, candlesticks or funnels, to decorative items like ear rings and hair clips. The earliest examples of pewter come from ancient Egypt, around 1450 BC. The use of pewter

4142-565: The Middle East, people began alloying copper with zinc to form brass. Ancient civilizations took into account the mixture and the various properties it produced, such as hardness , toughness and melting point, under various conditions of temperature and work hardening , developing much of the information contained in modern alloy phase diagrams . For example, arrowheads from the Chinese Qin dynasty (around 200 BC) were often constructed with

4251-516: The aerospace industry, to beryllium-copper alloys for non-sparking tools. An alloy is a mixture of chemical elements , which forms an impure substance (admixture) that retains the characteristics of a metal. An alloy is distinct from an impure metal in that, with an alloy, the added elements are well controlled to produce desirable properties, while impure metals such as wrought iron are less controlled, but are often considered useful. Alloys are made by mixing two or more elements, at least one of which

4360-414: The air, readily combines with most metals to form metal oxides ; especially at higher temperatures encountered during alloying. Great care is often taken during the alloying process to remove excess impurities, using fluxes , chemical additives, or other methods of extractive metallurgy . Alloying a metal is done by combining it with one or more other elements. The most common and oldest alloying process

4469-420: The alloy a unique and low melting point, and no liquid/solid slush transition. Alloying elements are added to a base metal, to induce hardness , toughness , ductility, or other desired properties. Most metals and alloys can be work hardened by creating defects in their crystal structure. These defects are created during plastic deformation by hammering, bending, extruding, et cetera, and are permanent unless

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4578-429: The alloy. However, most alloys were not created until the 1900s, such as various aluminium, titanium , nickel , and magnesium alloys . Some modern superalloys , such as incoloy , inconel, and hastelloy , may consist of a multitude of different elements. An alloy is technically an impure metal, but when referring to alloys, the term impurities usually denotes undesirable elements. Such impurities are introduced from

4687-444: The atomic arrangement that forms the alloy. They can be further classified as homogeneous (consisting of a single phase), or heterogeneous (consisting of two or more phases) or intermetallic . An alloy may be a solid solution of metal elements (a single phase, where all metallic grains (crystals) are of the same composition) or a mixture of metallic phases (two or more solutions, forming a microstructure of different crystals within

4796-452: The barrel. It is still widely used today for springs, bearings, bushings, automobile transmission pilot bearings, and similar fittings, and is particularly common in the bearings of small electric motors . Phosphor bronze is particularly suited to precision-grade bearings and springs. It is also used in guitar and piano strings. Unlike steel, bronze struck against a hard surface will not generate sparks, so it (along with beryllium copper )

4905-635: The base metal. Unlike steel, in which the solid solution separates into different crystal phases (carbide and ferrite), precipitation hardening alloys form different phases within the same crystal. These intermetallic alloys appear homogeneous in crystal structure, but tend to behave heterogeneously, becoming hard and somewhat brittle. In 1906, precipitation hardening alloys were discovered by Alfred Wilm . Precipitation hardening alloys, such as certain alloys of aluminium, titanium, and copper, are heat-treatable alloys that soften when quenched (cooled quickly), and then harden over time. Wilm had been searching for

5014-554: The base metals and alloying elements, but are removed during processing. For instance, sulfur is a common impurity in steel. Sulfur combines readily with iron to form iron sulfide , which is very brittle, creating weak spots in the steel. Lithium , sodium and calcium are common impurities in aluminium alloys, which can have adverse effects on the structural integrity of castings. Conversely, otherwise pure-metals that contain unwanted impurities are often called "impure metals" and are not usually referred to as alloys. Oxygen, present in

5123-473: The battle of David and Goliath in I Samuel 17:5-6;38 (also see II Chron. 12:10). Alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Most alloys are metallic and show good electrical conductivity , ductility , opacity , and luster , and may have properties that differ from those of

5232-528: The bell has been ceremonially struck five times a year: It was also rung on September 11, 2002, to commemorate the first anniversary of the September 11, 2001, terrorist attacks . The bell does not have a clapper; instead, it is sounded by striking it with a large wooden log. The pavilion that houses the bell, known as the Belfry of Friendship, was built by South Korean craftsmen over a period of ten months. Its design

5341-426: The carbon atoms are said to be in solution in the iron, forming a particular single, homogeneous, crystalline phase called austenite . If the steel is cooled slowly, the carbon can diffuse out of the iron and it will gradually revert to its low temperature allotrope. During slow cooling, the carbon atoms will no longer be as soluble with the iron, and will be forced to precipitate out of solution, nucleating into

5450-502: The crystals internally. Some alloys, such as electrum —an alloy of silver and gold —occur naturally. Meteorites are sometimes made of naturally occurring alloys of iron and nickel , but are not native to the Earth. One of the first alloys made by humans was bronze, which is a mixture of the metals tin and copper. Bronze was an extremely useful alloy to the ancients, because it is much stronger and harder than either of its components. Steel

5559-427: The elements via solid-state diffusion . By adding another element to a metal, differences in the size of the atoms create internal stresses in the lattice of the metallic crystals; stresses that often enhance its properties. For example, the combination of carbon with iron produces steel, which is stronger than iron, its primary element. The electrical and thermal conductivity of alloys is usually lower than that of

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5668-466: The first airplane engine in 1903. During the time between 1865 and 1910, processes for extracting many other metals were discovered, such as chromium, vanadium, tungsten, iridium , cobalt , and molybdenum, and various alloys were developed. Prior to 1910, research mainly consisted of private individuals tinkering in their own laboratories. However, as the aircraft and automotive industries began growing, research into alloys became an industrial effort in

5777-416: The first century, and was introduced in Europe during the 1700s, where molten pig iron was stirred while exposed to the air, to remove the carbon by oxidation . In 1858, Henry Bessemer developed a process of steel-making by blowing hot air through liquid pig iron to reduce the carbon content. The Bessemer process led to the first large scale manufacture of steel. Steel is an alloy of iron and carbon, but

5886-499: The first stainless steel. Due to their high reactivity, most metals were not discovered until the 19th century. A method for extracting aluminium from bauxite was proposed by Humphry Davy in 1807, using an electric arc . Although his attempts were unsuccessful, by 1855 the first sales of pure aluminium reached the market. However, as extractive metallurgy was still in its infancy, most aluminium extraction-processes produced unintended alloys contaminated with other elements found in

5995-400: The form of a high-manganese pig-iron called spiegeleisen ), which helped remove impurities such as phosphorus and oxygen; a process adopted by Bessemer and still used in modern steels (albeit in concentrations low enough to still be considered carbon steel). Afterward, many people began experimenting with various alloys of steel without much success. However, in 1882, Robert Hadfield , being

6104-626: The former Upper Reservation of Fort MacArthur . The Korean Friendship Bell is modeled after the Divine Bell of King Seongdeok the Great of Silla (also known as the Emille Bell ), The Emille Bell was cast in 771 for Bongdeok Temple and is currently housed at the National Museum of Gyeongju . Designated as National Treasure of Korea number 29 in 1962, the Emille Bell holds historical significance. It

6213-545: The high electrical conductivity of pure copper, low-friction properties of bearing bronze (bronze that has a high lead content— 6–8%), resonant qualities of bell bronze (20% tin, 80% copper), and resistance to corrosion by seawater of several bronze alloys. The melting point of bronze varies depending on the ratio of the alloy components and is about 950 °C (1,742 °F). Bronze is usually nonmagnetic, but certain alloys containing iron or nickel may have magnetic properties. Typically bronze oxidizes only superficially; once

6322-681: The highest form of sculpture in Ancient Greek art , though survivals are few, as bronze was a valuable material in short supply in the Late Antique and medieval periods. Many of the most famous Greek bronze sculptures are known through Roman copies in marble, which were more likely to survive. In India, bronze sculptures from the Kushana ( Chausa hoard ) and Gupta periods ( Brahma from Mirpur-Khas , Akota Hoard, Sultanganj Buddha ) and later periods ( Hansi Hoard) have been found. Indian Hindu artisans from

6431-479: The inscriptions they carry and from other sources, the case is clear. These were made in enormous quantities for elite burials, and also used by the living for ritual offerings. Though bronze is generally harder than wrought iron , with Vickers hardness of 60–258 vs. 30–80, the Bronze Age gave way to the Iron Age after a serious disruption of the tin trade: the population migrations of around 1200–1100 BC reduced

6540-474: The interstices, but some of the iron atoms are substituted by nickel and chromium atoms. The use of alloys by humans started with the use of meteoric iron , a naturally occurring alloy of nickel and iron. It is the main constituent of iron meteorites . As no metallurgic processes were used to separate iron from nickel, the alloy was used as it was. Meteoric iron could be forged from a red heat to make objects such as tools, weapons, and nails. In many cultures it

6649-551: The introduction of crucible steel around 300 BC. These steels were of poor quality, and the introduction of pattern welding , around the 1st century AD, sought to balance the extreme properties of the alloys by laminating them, to create a tougher metal. Around 700 AD, the Japanese began folding bloomery-steel and cast-iron in alternating layers to increase the strength of their swords, using clay fluxes to remove slag and impurities. This method of Japanese swordsmithing produced one of

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6758-405: The iron crystals. When rapidly cooled, a diffusionless (martensite) transformation occurs, in which the carbon atoms become trapped in solution. This causes the iron crystals to deform as the crystal structure tries to change to its low temperature state, leaving those crystals very hard but much less ductile (more brittle). While the high strength of steel results when diffusion and precipitation

6867-824: The main alloying ingredient. They are commonly used in architectural applications. Plastic bronze contains a significant quantity of lead, which makes for improved plasticity, and was possibly used by the ancient Greeks in ship construction. Silicon bronze has a composition of Si: 2.80–3.80%, Mn: 0.50–1.30%, Fe: 0.80% max., Zn: 1.50% max., Pb: 0.05% max., Cu: balance. Other bronze alloys include aluminium bronze , phosphor bronze , manganese bronze, bell metal , arsenical bronze , speculum metal , bismuth bronze , and cymbal alloys . Copper-based alloys have lower melting points than steel or iron and are more readily produced from their constituent metals. They are generally about 10 percent denser than steel, although alloys using aluminum or silicon may be slightly less dense. Bronze

6976-458: The manufacture of various types of medals for centuries, and " bronze medals " are known in contemporary times for being awarded for third place in sporting competitions and other events. The term is now often used for third place even when no actual bronze medal is awarded. The usage in part arose from the trio of gold , silver and bronze to represent the first three Ages of Man in Greek mythology:

7085-643: The massive bronze doors to the United States Supreme Court Building in Washington, DC. Before it became possible to produce glass with acceptably flat surfaces, bronze was a standard material for mirrors. Bronze was used for this purpose in many parts of the world, probably based on independent discoveries. Bronze mirrors survive from the Egyptian Middle Kingdom (2040–1750 BC), and China from at least c.  550 BC . In Europe,

7194-450: The metal is recrystallized . Otherwise, some alloys can also have their properties altered by heat treatment . Nearly all metals can be softened by annealing , which recrystallizes the alloy and repairs the defects, but not as many can be hardened by controlled heating and cooling. Many alloys of aluminium, copper, magnesium , titanium, and nickel can be strengthened to some degree by some method of heat treatment, but few respond to this to

7303-485: The metal). Examples of alloys include red gold ( gold and copper ), white gold (gold and silver ), sterling silver (silver and copper), steel or silicon steel ( iron with non-metallic carbon or silicon respectively), solder , brass , pewter , duralumin , bronze , and amalgams . Alloys are used in a wide variety of applications, from the steel alloys, used in everything from buildings to automobiles to surgical tools, to exotic titanium alloys used in

7412-794: The names of individual alloys. This is done (at least in part) to prevent database searches from failing merely because of errors or disagreements in the naming of historic copper alloys. The word bronze (1730–1740) is borrowed from Middle French bronze (1511), itself borrowed from Italian bronzo ' bell metal, brass ' (13th century, transcribed in Medieval Latin as bronzium ) from either: The discovery of bronze enabled people to create metal objects that were harder and more durable than previously possible. Bronze tools , weapons , armor , and building materials such as decorative tiles were harder and more durable than their stone and copper (" Chalcolithic ") predecessors. Initially, bronze

7521-455: The ore; the most abundant of which was copper. These aluminium-copper alloys (at the time termed "aluminum bronze") preceded pure aluminium, offering greater strength and hardness over the soft, pure metal, and to a slight degree were found to be heat treatable. However, due to their softness and limited hardenability these alloys found little practical use, and were more of a novelty, until the Wright brothers used an aluminium alloy to construct

7630-418: The other constituent. This is called a substitutional alloy . Examples of substitutional alloys include bronze and brass, in which some of the copper atoms are substituted with either tin or zinc atoms respectively. In the case of the interstitial mechanism, one atom is usually much smaller than the other and can not successfully substitute for the other type of atom in the crystals of the base metal. Instead,

7739-416: The other. However, in other alloys, the insoluble elements may not separate until after crystallization occurs. If cooled very quickly, they first crystallize as a homogeneous phase, but they are supersaturated with the secondary constituents. As time passes, the atoms of these supersaturated alloys can separate from the crystal lattice, becoming more stable, and forming a second phase that serves to reinforce

7848-505: The pavilion was restricted from September through December. The City of Los Angeles rededicated the Bell during a public ceremony on January 10, 2014, after the Korean Ministry of Culture, Sports and Tourism contributed more than US$ 300,000 (equivalent to $ 386,000 in 2023) to hire bell masters for the restoration. Access to the Bell was closed for more than a year following the start of

7957-567: The period of the Chola empire in Tamil Nadu used bronze to create intricate statues via the lost-wax casting method with ornate detailing depicting the deities of Hinduism . The art form survives to this day, with many silpis, craftsmen, working in the areas of Swamimalai and Chennai . In antiquity other cultures also produced works of high art using bronze. For example: in Africa, the bronze heads of

8066-400: The phenomenon was not provided until 1919, duralumin was one of the first "age hardening" alloys used, becoming the primary building material for the first Zeppelins , and was soon followed by many others. Because they often exhibit a combination of high strength and low weight, these alloys became widely used in many forms of industry, including the construction of modern aircraft . When

8175-424: The preferred metal for bells in the form of a high tin bronze alloy known as bell metal , which is typically about 23% tin. Nearly all professional cymbals are made from bronze, which gives a desirable balance of durability and timbre . Several types of bronze are used, commonly B20 bronze , which is roughly 20% tin, 80% copper, with traces of silver, or the tougher B8 bronze made from 8% tin and 92% copper. As

8284-441: The presence of nitrogen. This increases the chance of contamination from any contacting surface, and so must be melted in vacuum induction-heating and special, water-cooled, copper crucibles . However, some metals and solutes, such as iron and carbon, have very high melting-points and were impossible for ancient people to melt. Thus, alloying (in particular, interstitial alloying) may also be performed with one or more constituents in

8393-452: The proprietary Oilite and similar material for bearings. Aluminum bronze is hard and wear-resistant, and is used for bearings and machine tool ways. The Doehler Die Casting Co. of Toledo, Ohio were known for the production of Brastil , a high tensile corrosion resistant bronze alloy. The Seagram Building on New York City 's Park Avenue is the "iconic glass box sheathed in bronze, designed by Mies van der Rohe ." The Seagram Building

8502-636: The pure elements such as increased strength or hardness. In some cases, an alloy may reduce the overall cost of the material while preserving important properties. In other cases, the mixture imparts synergistic properties such as corrosion resistance or mechanical strength. In an alloy, the atoms are joined by metallic bonding rather than by covalent bonds typically found in chemical compounds. The alloy constituents are usually measured by mass percentage for practical applications, and in atomic fraction for basic science studies. Alloys are usually classified as substitutional or interstitial alloys , depending on

8611-415: The pure metals. The physical properties, such as density , reactivity , Young's modulus of an alloy may not differ greatly from those of its base element, but engineering properties such as tensile strength , ductility, and shear strength may be substantially different from those of the constituent materials. This is sometimes a result of the sizes of the atoms in the alloy, because larger atoms exert

8720-443: The purest steel-alloys of the ancient world. While the use of iron started to become more widespread around 1200 BC, mainly because of interruptions in the trade routes for tin, the metal was much softer than bronze. However, very small amounts of steel, (an alloy of iron and around 1% carbon), was always a byproduct of the bloomery process. The ability to modify the hardness of steel by heat treatment had been known since 1100 BC, and

8829-415: The rare material was valued for the manufacture of tools and weapons. Because the ancients could not produce temperatures high enough to melt iron fully, the production of steel in decent quantities did not occur until the introduction of blister steel during the Middle Ages. This method introduced carbon by heating wrought iron in charcoal for long periods of time, but the absorption of carbon in this manner

8938-454: The ready availability of silicon bronze brazing rod, which allows color-matched repair of defects in castings. Aluminum is also used for the structural metal aluminum bronze. Bronze parts are tough and typically used for bearings , clips, electrical connectors and springs . Bronze also has low friction against dissimilar metals, making it important for cannons prior to modern tolerancing , where iron cannonballs would otherwise stick in

9047-612: The resulting aluminium alloy will have much greater strength . Adding a small amount of non-metallic carbon to iron trades its great ductility for the greater strength of an alloy called steel. Due to its very-high strength, but still substantial toughness , and its ability to be greatly altered by heat treatment , steel is one of the most useful and common alloys in modern use. By adding chromium to steel, its resistance to corrosion can be enhanced, creating stainless steel , while adding silicon will alter its electrical characteristics, producing silicon steel . Like oil and water,

9156-674: The resulting alloy was stronger and easier to cast. Also, unlike those of arsenic , metallic tin and the fumes from tin refining are not toxic . Tin became the major non-copper ingredient of bronze in the late 3rd millennium BC. Ores of copper and the far rarer tin are not often found together (exceptions include Cornwall in the United Kingdom, one ancient site in Thailand and one in Iran), so serious bronze work has always involved trade with other regions. Tin sources and trade in ancient times had

9265-428: The same degree as does steel. The base metal iron of the iron-carbon alloy known as steel, undergoes a change in the arrangement ( allotropy ) of the atoms of its crystal matrix at a certain temperature (usually between 820 °C (1,500 °F) and 870 °C (1,600 °F), depending on carbon content). This allows the smaller carbon atoms to enter the interstices of the iron crystal. When this diffusion happens,

9374-415: The shipping of tin around the Mediterranean and from Britain, limiting supplies and raising prices. As the art of working in iron improved, iron became cheaper and improved in quality. As later cultures advanced from hand- wrought iron to machine- forged iron (typically made with trip hammers powered by water), blacksmiths also learned how to make steel . Steel is stronger and harder than bronze and holds

9483-400: The smaller atoms become trapped in the interstitial sites between the atoms of the crystal matrix. This is referred to as an interstitial alloy . Steel is an example of an interstitial alloy, because the very small carbon atoms fit into interstices of the iron matrix. Stainless steel is an example of a combination of interstitial and substitutional alloys, because the carbon atoms fit into

9592-456: The term alloy steel usually only refers to steels that contain other elements— like vanadium , molybdenum , or cobalt —in amounts sufficient to alter the properties of the base steel. Since ancient times, when steel was used primarily for tools and weapons, the methods of producing and working the metal were often closely guarded secrets. Even long after the Age of Enlightenment , the steel industry

9701-469: The tin content in a bell or cymbal rises, the timbre drops. Bronze is also used for the windings of steel and nylon strings of various stringed instruments such as the double bass , piano, harpsichord , and guitar. Bronze strings are commonly reserved on pianoforte for the lower pitch tones, as they possess a superior sustain quality to that of high-tensile steel. Bronzes of various metallurgical properties are widely used in struck idiophones around

9810-439: The unusual and desirable property of expanding slightly just before they set, thus filling the finest details of a mould. Then, as the bronze cools, it shrinks a little, making it easier to separate from the mould. The Assyrian king Sennacherib (704–681 BC) claims to have been the first to cast monumental bronze statues (of up to 30 tonnes) using two-part moulds instead of the lost-wax method . Bronze statues were regarded as

9919-419: The wide employment of stainless steel owing to its combination of toughness and resistance to salt water corrosion. Bronze is still commonly used in ship propellers and submerged bearings. In the 20th century, silicon was introduced as the primary alloying element, creating an alloy with wide application in industry and the major form used in contemporary statuary . Sculptors may prefer silicon bronze because of

10028-637: The world was by the Roman Bronze Works and General Bronze Corporation in 1952. The material used for the fountain, known as statuary bronze, is a quaternary alloy made of copper, zinc, tin, and lead, and traditionally golden brown in color. This was made for the Andrew W. Mellon Memorial Fountain in Federal Triangle in Washington, DC. Another example of the massive, ornate design projects of bronze, and attributed to General Bronze/Roman Bronze Works were

10137-705: The world, notably bells, singing bowls, gongs , cymbals, and other idiophones from Asia. Examples include Tibetan singing bowls , temple bells of many sizes and shapes, Javanese gamelan , and other bronze musical instruments . The earliest bronze archeological finds in Indonesia date from 1–2 BC, including flat plates probably suspended and struck by a wooden or bone mallet. Ancient bronze drums from Thailand and Vietnam date back 2,000 years. Bronze bells from Thailand and Cambodia date back to 3600 BC. Some companies are now making saxophones from phosphor bronze (3.5 to 10% tin and up to 1% phosphorus content). Bell bronze/B20

10246-824: Was another common alloy. However, in ancient times, it could only be created as an accidental byproduct from the heating of iron ore in fires ( smelting ) during the manufacture of iron. Other ancient alloys include pewter , brass and pig iron . In the modern age, steel can be created in many forms. Carbon steel can be made by varying only the carbon content, producing soft alloys like mild steel or hard alloys like spring steel . Alloy steels can be made by adding other elements, such as chromium , molybdenum , vanadium or nickel , resulting in alloys such as high-speed steel or tool steel . Small amounts of manganese are usually alloyed with most modern steels because of its ability to remove unwanted impurities, like phosphorus , sulfur and oxygen , which can have detrimental effects on

10355-422: Was applied as a paste and then heated until the mercury vaporized, leaving the gold, silver, or tin behind. Mercury was often used in mining, to extract precious metals like gold and silver from their ores. Many ancient civilizations alloyed metals for purely aesthetic purposes. In ancient Egypt and Mycenae , gold was often alloyed with copper to produce red-gold, or iron to produce a bright burgundy-gold. Gold

10464-483: Was commissioned by the King of Syracuse to find a way to check the purity of the gold in a crown, leading to the famous bath-house shouting of "Eureka!" upon the discovery of Archimedes' principle . The term pewter covers a variety of alloys consisting primarily of tin. As a pure metal, tin is much too soft to use for most practical purposes. However, during the Bronze Age , tin was a rare metal in many parts of Europe and

10573-429: Was followed by the Iron Age starting about 1300 BC and reaching most of Eurasia by about 500 BC, although bronze continued to be much more widely used than it is in modern times. Because historical artworks were often made of brasses (copper and zinc) and bronzes of different metallic compositions, modern museum and scholarly descriptions of older artworks increasingly use the generalized term "copper alloy" instead of

10682-520: Was made out of copper and arsenic or from naturally or artificially mixed ores of those metals, forming arsenic bronze . The earliest known arsenic-copper-alloy artifacts come from a Yahya Culture (Period V 3800-3400 BCE) site, at Tal-i-Iblis on the Iranian plateau , and were smelted from native arsenical copper and copper-arsenides, such as algodonite and domeykite . The earliest tin-copper-alloy artifact has been dated to c.  4650 BC , in

10791-468: Was mentioned in the account of Moses holding up a bronze snake on a pole in Numbers Ch.21. In First Kings, it is mentioned that Hiram was very skilled in working with bronze, and he made many furnishings for Solomon's Temple including pillars, capitals, stands, wheels, bowls, and plates, some of which were highly decorative (see I Kings 7:13-47). Bronze was also widely used as battle armor and helmet, as in

10900-416: Was not generally considered an alloy until the decades between 1930 and 1970 (primarily due to the work of scientists like William Chandler Roberts-Austen , Adolf Martens , and Edgar Bain ), so "alloy steel" became the popular term for ternary and quaternary steel-alloys. After Benjamin Huntsman developed his crucible steel in 1740, he began experimenting with the addition of elements like manganese (in

11009-424: Was not only the most expensive building of its time — $ 36 million — but it was the first building in the world with floor-to-ceiling glass walls. Mies van der Rohe achieved the crisp edges that were custom-made with specific detailing by General Bronze and "even the screws that hold in the fixed glass-plate windows were made of brass." Bronze is widely used for casting bronze sculptures . Common bronze alloys have

11118-450: Was often found alloyed with silver or other metals to produce various types of colored gold . These metals were also used to strengthen each other, for more practical purposes. Copper was often added to silver to make sterling silver , increasing its strength for use in dishes, silverware, and other practical items. Quite often, precious metals were alloyed with less valuable substances as a means to deceive buyers. Around 250 BC, Archimedes

11227-476: Was on hand; the metal of the 12th-century English Gloucester Candlestick is bronze containing a mixture of copper, zinc, tin, lead, nickel, iron, antimony, arsenic and an unusually large amount of silver – between 22.5% in the base and 5.76% in the pan below the candle. The proportions of this mixture suggest that the candlestick was made from a hoard of old coins. The 13th-century Benin Bronzes are in fact brass, and

11336-566: Was presented by the South Korean government to the United States to celebrate the bicentennial of the U.S. and to symbolize friendship between the two countries. The effort was coordinated by Philip Ahn , a Korean American actor. It was dedicated on October 3, 1976, and declared Los Angeles Historic-Cultural Monument No. 187 on May 3, 1978. The bell is struck 13 times on the first Saturday of each month at 11:30 AM. Beginning in 2010,

11445-588: Was shaped by cold hammering into knives and arrowheads. They were often used as anvils. Meteoric iron was very rare and valuable, and difficult for ancient people to work . Iron is usually found as iron ore on Earth, except for one deposit of native iron in Greenland , which was used by the Inuit . Native copper, however, was found worldwide, along with silver, gold, and platinum , which were also used to make tools, jewelry, and other objects since Neolithic times. Copper

11554-587: Was the first time that an entire building was sheathed in bronze. The General Bronze Corporation fabricated 3,200,000 pounds (1,600 tons) of bronze at its plant in Garden City, New York . The Seagram Building is a 38-story, 516-foot bronze-and- topaz -tinted glass building. The building looks like a "squarish 38-story tower clad in a restrained curtain wall of metal and glass." "Bronze was selected because of its color, both before and after aging, its corrosion resistance, and its extrusion properties. In 1958, it

11663-492: Was the hardest of these metals, and the most widely distributed. It became one of the most important metals to the ancients. Around 10,000 years ago in the highlands of Anatolia (Turkey), humans learned to smelt metals such as copper and tin from ore . Around 2500 BC, people began alloying the two metals to form bronze, which was much harder than its ingredients. Tin was rare, however, being found mostly in Great Britain. In

11772-557: Was very competitive and manufacturers went through great lengths to keep their processes confidential, resisting any attempts to scientifically analyze the material for fear it would reveal their methods. For example, the people of Sheffield , a center of steel production in England, were known to routinely bar visitors and tourists from entering town to deter industrial espionage . Thus, almost no metallurgical information existed about steel until 1860. Because of this lack of understanding, steel

11881-556: Was widespread across Europe, from France to Norway and Britain (where most of the ancient tin was mined) to the Near East. The alloy was also used in China and the Far East, arriving in Japan around 800 AD, where it was used for making objects like ceremonial vessels, tea canisters, or chalices used in shinto shrines. The first known smelting of iron began in Anatolia , around 1800 BC. Called

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