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Copper alloys

ContentsArticles

Brass 1Bronze 11Selective leaching 17Free machining steel 18

ReferencesArticle Sources and Contributors 20Image Sources, Licenses and Contributors 21

Article LicensesLicense 22

Brass 1

Brass

Brass die, along with zinc and copper samples.

Brass is an alloy of copper and zinc; the proportions of zinc andcopper can be varied to create a range of brasses with varyingproperties.[1]

By comparison, bronze is principally an alloy of copper and tin.[2]

Bronze does not necessarily contain tin, and a variety of alloys ofcopper, including alloys with arsenic, phosphorus, aluminium,manganese, and silicon, are commonly termed "bronze". The term isapplied to a variety of brasses and the distinction is largely historical,[3]

both terms having a common antecedent in the term latten.

Brass is a substitutional alloy. It is used for decoration for its bright gold-like appearance; for applications where lowfriction is required such as locks, gears, bearings, doorknobs, ammunition casings and valves; for plumbing andelectrical applications; and extensively in musical instruments such as horns and bells for its acoustic properties. It isalso used in zippers. Brass is often used in situations where it is important that sparks not be struck, as in fittings andtools around explosive gases.[4]

Properties

Microstructure of rolled and annealed brass(400X magnification)

The malleability and acoustic properties of brass have made it themetal of choice for musical instruments such as the trombone, tuba,trumpet, cornet, baritone horn, euphonium, tenor horn, and Frenchhorn which are collectively known as the brass within an orchestra.Even though the saxophone is classified as a woodwind instrument andthe harmonica is a free reed aerophone, both are also often made frombrass. In organ pipes of the reed family, brass strips (called tongues)are used as the reeds, which beat against the shallot (or beat "through"the shallot in the case of a "free" reed). Although not part of the brasssection, snare drums are also sometimes made of brass.

Brass has higher malleability than bronze or zinc. The relatively lowmelting point of brass (900 to 940C, 1652 to 1724F, depending on composition) and its flow characteristics makeit a relatively easy material to cast. By varying the proportions of copper and zinc, the properties of the brass can bechanged, allowing hard and soft brasses. The density of brass is approximately .303lb/cubic inch, 8.4 to 8.73gramsper cubic centimetre.[5]

Today almost 90% of all brass alloys are recycled.[6] Because brass is not ferromagnetic, it can be separated fromferrous scrap by passing the scrap near a powerful magnet. Brass scrap is collected and transported to the foundrywhere it is melted and recast into billets. Billets are heated and extruded into the desired form and size.Aluminium makes brass stronger and more corrosion resistant. Aluminium also causes a highly beneficial hard layerof aluminium oxide (Al2O3) to be formed on the surface that is thin, transparent and self-healing. Tin has a similareffect and finds its use especially in sea water applications (naval brasses). Combinations of iron, aluminium, siliconand manganese make brass wear and tear resistant.[7]

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Lead contentTo enhance the machinability of brass, lead is often added in concentrations of around 2%. Since lead has a lowermelting point than the other constituents of the brass, it tends to migrate towards the grain boundaries in the form ofglobules as it cools from casting. The pattern the globules form on the surface of the brass increases the availablelead surface area which in turn affects the degree of leaching. In addition, cutting operations can smear the leadglobules over the surface. These effects can lead to significant lead leaching from brasses of comparatively low leadcontent.[8]

Silicon is an alternative to lead; however, when silicon is used in a brass alloy, the scrap must never be mixed withleaded brass scrap because of contamination and safety problems.[9]

In October 1999 the California State Attorney General sued 13 key manufacturers and distributors over lead content.In laboratory tests, state researchers found the average brass key, new or old, exceeded the California Proposition 65limits by an average factor of 19, assuming handling twice a day.[10] In April 2001 manufacturers agreed to reducelead content to 1.5%, or face a requirement to warn consumers about lead content. Keys plated with other metals arenot affected by the settlement, and may continue to use brass alloys with higher percentage of lead content.[11][12]

Also in California, lead-free materials must be used for "each component that comes into contact with the wettedsurface of pipes and pipe fittings, plumbing fittings and fixtures." On January 1, 2010, the maximum amount of leadin "lead-free brass" in California was reduced from 4% to 0.25% lead. The common practice of using pipes forelectrical grounding is discouraged, as it accelerates lead corrosion.[13][14]

Corrosion-resistant brass for harsh environments

Brass sampling cock with stainless steel handle.

The so-called dezincification resistant (DZR or DR) brasses areused where there is a large corrosion risk and where normalbrasses do not meet the standards. Applications with high watertemperatures, chlorides present or deviating water qualities (softwater) play a role. DZR-brass is excellent in water boiler systems.This brass alloy must be produced with great care, with specialattention placed on a balanced composition and proper productiontemperatures and parameters to avoid long-term failures.

Germicidal and antimicrobial applications

See also: Antimicrobial properties of copper, Copper alloys inaquaculture

The copper in brass makes brass germicidal. Depending upon the type and concentration of pathogens and themedium they are in, brass kills these microorganisms within a few minutes to hours of contact.[15][][]

The bactericidal properties of brass have been observed for centuries and were confirmed in the laboratory in1983.[16] Subsequent experiments by research groups around the world reconfirmed the antimicrobial efficacy ofbrass, as well as copper and other copper alloys (see Antimicrobial copper-alloy touch surfaces).[15][][] Extensivestructural membrane damage to bacteria was noted after being exposed to copper.In 2007, U.S. Department of Defenses Telemedicine and Advanced Technology Research Center (TATRC) began to study the antimicrobial properties of copper alloys, including four brasses (C87610, C69300, C26000, C46400) in a multi-site clinical hospital trial conducted at the Memorial Sloan-Kettering Cancer Center (New York City), the Medical University of South Carolina, and the Ralph H. Johnson VA Medical Center (South Carolina).[][17]

Commonly touched items, such as bed rails, over-the-bed tray tables, chair arms, nurse's call buttons, IV poles, etc. were retrofitted with antimicrobial copper alloys in certain patient rooms (i.e., the coppered rooms) in the Intensive

Brass 3

Care Unit (ICU). Early results disclosed in 2011 indicate that the coppered rooms demonstrated a 97% reduction insurface pathogens versus the non-coppered rooms. This reduction is the same level achieved by terminal cleaningregimens conducted after patients vacate their rooms. Furthermore, of critical importance to health careprofessionals, the preliminary results indicated that patients in the coppered ICU rooms had a 40.4% lower risk ofcontracting a hospital acquired infection versus patients in non-coppered ICU rooms.[][18][19] The U.S. Departmentof Defense investigation contract, which is ongoing, will also evaluate the effectiveness of copper alloy touchsurfaces to prevent the transfer of microbes to patients and the transfer of microbes from patients to touch surfaces,as well as the potential efficacy of copper-alloy based components to improve indoor air quality.In the U.S., the Environmental Protection Agency regulates the registration of antimicrobial products. Afterextensive antimicrobial testing according to the Agencys stringent test protocols, 355 copper alloys, including manybrasses, were found to kill more than 99.9% of methicillin-resistant Staphylococcus aureus (MRSA), E. coliO157:H7, Pseudomonas aeruginosa, Staphylococcus aureus, Enterobacter aerogenes, and vancomycin-resistantEnterococci (VRE) within two hours of contact.[15][] Normal tarnishing was found to not impair antimicrobialeffectiveness.Antimicrobial tests have also revealed significant reductions of MRSA as well as two strains of epidemic MRSA(EMRSA-1 and EMRSA-16) on brass (C24000 with 80% Cu) at room temperature (22 C) within three hours.Complete kills of the pathogens were observed within 4 12 hours. These tests were performed under wet exposureconditions. The kill timeframes, while impressive, are nevertheless longer than for pure copper, where killtimeframes ranged between 45 to 90 minutes.[]

A novel assay that mimics dry bacterial exposure to touch surfaces was developed because this test method isthought to more closely replicate real world touch surface exposure conditions. In these conditions, copper alloysurfaces were found to kill several million Colony Forming Units of Escherichia coli within minutes.[] Thisobservation, and the fact that kill timeframes shorten as the percentage of copper in an alloy increases, is proof thatcopper is the ingredient in brass and other copper alloys that kills the microbes.[20]

The mechanisms of antimicrobial action by copper and its alloys, including brass, is a subject of intense and ongoinginvestigation.[][][] It is believed that the mechanisms are multifaceted and include the following: 1) Potassium orglutamate leakage through the outer membrane of bacteria; 2) Osmotic balance disturbances; 3) Binding to proteinsthat do not require or utilize copper; 4) Oxidative stress by hydrogen peroxide generation.Research is being conducted at this time to determine whether brass, copper, and other copper alloys can help toreduce cross contamination in public facilities and reduce the incidence of nosocomial infections (hospital acquiredinfections) in healthcare facilities.Also, owing to its antimicrobial/algaecidal properties that prevent biofouling, in conjunction with its strong structuraland corrosion-resistant benefits for marine environments, brass alloy netting cages are currently being deployed incommercial-scale aquaculture operations in Asia, South America, and the USA.

Brass 4

Season cracking

Cracking in brass caused by ammonia attack

Brass is susceptible to stress corrosioncracking, especially from ammonia orsubstances containing or releasing ammonia.The problem is sometimes known as seasoncracking after it was first discovered in brasscartridge cases used for rifle ammunitionduring the 1920s in the Indian Army. Theproblem was caused by high residualstresses from cold forming of the casesduring manufacture, together with chemicalattack from traces of ammonia in theatmosphere. The cartridges were stored in stables and the ammonia concentration rose during the hot summermonths, so initiating brittle cracks. The problem was resolved by annealing the cases, and storing the cartridgeselsewhere.

Brass types Admiralty brass contains 30% zinc, and 1% tin which inhibits dezincification in many environments. Aich's alloy typically contains 60.66% copper, 36.58% zinc, 1.02% tin, and 1.74% iron. Designed for use in

marine service owing to its corrosion resistance, hardness and toughness. A characteristic application is to theprotection of ships' bottoms, but more modern methods of cathodic protection have rendered its use less common.Its appearance resembles that of gold.[21]

Alpha brasses with less than 35% zinc, are malleable, can be worked cold, and are used in pressing, forging, orsimilar applications. They contain only one phase, with face-centered cubic crystal structure.

Prince's metal or Prince Rupert's metal is a type of alpha brass containing 75% copper and 25% zinc. Due to itsbeautiful yellow color, it is used as an imitation of gold.[22] The alloy was named after Prince Rupert of the Rhine.

Alpha-beta brass (Muntz metal), also called duplex brass, is 3545% zinc and is suited for hot working. Itcontains both and ' phase; the '-phase is body-centered cubic and is harder and stronger than . Alpha-betabrasses are usually worked hot.

Aluminium brass contains aluminium, which improves its corrosion resistance. It is used for seawater service[23]

and also in Euro coins (Nordic gold). Arsenical brass contains an addition of arsenic and frequently aluminium and is used for boiler fireboxes. Beta brasses, with 4550% zinc content, can only be worked hot, and are harder, stronger, and suitable for

casting. Cartridge brass is a 30% zinc brass with good cold working properties. Used for ammunition cases. Common brass, or rivet brass, is a 37% zinc brass, cheap and standard for cold working. DZR brass is dezincification resistant brass with a small percentage of arsenic. Gilding metal is the softest type of brass commonly available. An alloy of 95% copper and 5% zinc, gilding

metal is typically used for ammunition bullet "jackets", e.g. full metal jacket bullets. High brass contains 65% copper and 35% zinc, has a high tensile strength and is used for springs, screws, and

rivets. Leaded brass is an alpha-beta brass with an addition of lead. It has excellent machinability. Lead-free brass as defined by California Assembly Bill AB 1953 contains "not more than 0.25 percent lead

content".[13]

Low brass is a copper-zinc alloy containing 20% zinc with a light golden color and excellent ductility; it is usedfor flexible metal hoses and metal bellows.

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Manganese brass is a brass most notably used in making golden dollar coins in the United States. It containsroughly 70% copper, 29% zinc, and 1.3% manganese.[24]

Muntz metal is about 60% copper, 40% zinc and a trace of iron, used as a lining on boats. Naval brass, similar to admiralty brass, is 40% zinc and 1% tin. Nickel brass is composed of 70% copper, 24.5% zinc and 5.5% nickel used to make pound coins in the pound

sterling currency. Nordic gold, used in 10, 20 and 50 cts euro coins, contains 89% copper, 5% aluminium, 5% zinc, and 1% tin. Red brass is both an American term for the copper-zinc-tin alloy known as gunmetal, and an alloy which is

considered both a brass and a bronze. It typically contains 85% copper, 5% tin, 5% lead, and 5% zinc.[25][] Redbrass is also an alternative name for copper alloy C23000, which is composed of 1416% zinc, 0.05% iron andlead, and the remainder copper.[26] It may also refer to ounce metal, another copper-zinc-tin alloy.

Rich low brass (Tombac) is 15% zinc. It is often used in jewelry applications. Tonval brass (also called CW617N or CZ122 or OT58) is a copper-lead-zinc alloy.[27]

White brass contains more than 50% zinc and is too brittle for general use. The term may also refer to certaintypes of nickel silver alloys as well as Cu-Zn-Sn alloys with high proportions (typically 40%+) of tin and/or zinc,as well as predominantly zinc casting alloys with copper additive.

Yellow brass is an American term for 33% zinc brass.

HistoryAlthough forms of brass have been in use since prehistory,[28] its true nature as a copper-zinc alloy was notunderstood until the post medieval period because the zinc vapor which reacted with copper to make brass was notrecognised as a metal.[29] The King James Bible makes many references to "brass".[30] The Shakespearean Englishform of the word 'brass' can mean any bronze alloy, or copper, rather than the strict modern definition of brass.[citation needed] The earliest brasses may have been natural alloys made by smelting zinc-rich copper ores.[31] By theRoman period brass was being deliberately produced from metallic copper and zinc minerals using the cementationprocess and variations on this method continued until the mid-19th century.[32] It was eventually replaced byspeltering, the direct alloying of copper and zinc metal which was introduced to Europe in the 16th century.[31]

Early copper zinc alloysIn West Asia and the Eastern Mediterranean early copper zinc alloys are now known in small numbers from anumber of third Millennium BC sites in the Aegean, Iraq, the United Arab Emirates, Kalmykia, Turkmenistan andGeorgia and from 2nd Millennium BC sites in West India, Uzbekistan, Iran, Syria, Iraq and Israel.[33] However,isolated examples of copper-zinc alloys are known in China from as early as the 5th Millennium BC.[]

The compositions of these early "brass" objects are very variable and most have zinc contents of between 5% and15% wt which is lower than in brass produced by cementation.[34] These may be "natural alloys" manufactured bysmelting zinc rich copper ores in redox conditions. Many have similar tin contents to contemporary bronze artefactsand it is possible that some copper-zinc alloys were accidental and perhaps not even distinguished from copper.[34]

However the large number of copper-zinc alloys now known suggests that at least some were deliberatelymanufactured and many have zinc contents of more than 12% wt which would have resulted in a distinctive goldencolor.[34][35]

By the 8th7th century BC Assyrian cuneiform tablets mention the exploitation of the "copper of the mountains" andthis may refer to "natural" brass.[36] Oreichalkos, the Ancient Greek translation of this term, was later adapted to theLatin aurichalcum meaning "golden copper" which became the standard term for brass.[37] In the 4th century BCPlato knew oreichalkos as rare and nearly as valuable as gold[] and Pliny describes how aurichalcum had come fromCypriot ore deposits which had been exhausted by the 1st century AD.[38]

Brass 6

Brass making in the Roman WorldDuring the later part of first millennium BC the use of brass spread across a wide geographical area from Britain[]

and Spain[39] in the west to Iran, and India in the east.[40] This seems to have been encouraged by exports andinfluence from the Middle-East and eastern Mediterranean where deliberate production of brass from metallic copperand zinc ores had been introduced.[41] The 4th century BC writer Theopompus, quoted by Strabo, describes howheating earth from Andeira in Turkey produced "droplets of false silver", probably metallic zinc, which could beused to turn copper into oreichalkos.[42] In the 1st century BC the Greek Dioscorides seems to have recognised a linkbetween zinc minerals and brass describing how Cadmia (zinc oxide) was found on the walls of furnaces used to heateither zinc ore or copper and explaining that it can then be used to make brass.[43]

By the first century BC brass was available in sufficient supply to use as coinage in Phrygia and Bithynia,[44] andafter the Augustan currency reform of 23 BC it was also used to make Roman dupondii and sestertii.[45] The uniformuse of brass for coinage and military equipment across the Roman world may indicate a degree of state involvementin the industry,[46][] and brass even seems to have been deliberately boycotted by Jewish communities in Palestinebecause of its association with Roman authority.[]

Brass was produced by the cementation process where copper and zinc ore are heated together until zinc vapor isproduced which reacts with the copper. There is good archaeological evidence for this process and crucibles used toproduce brass by cementation have been found on Roman period sites including Xanten[] and Nidda[] in Germany,Lyon in France[47] and at a number of sites in Britain.[48] They vary in size from tiny acorn sized to large amphoraelike vessels but all have elevated levels of zinc on the interior and are lidded.[47] They show no signs of slag or metalprills suggesting that zinc minerals were heated to produce zinc vapor which reacted with metallic copper in a solidstate reaction. The fabric of these crucibles is porous, probably designed to prevent a build up of pressure, and manyhave small holes in the lids which may be designed to release pressure[47] or to add additional zinc minerals near theend of the process. Dioscorides mentioned that zinc minerals were used for both the working and finishing of brass,perhaps suggesting secondary additions.[49]

Brass made during the early Roman period seems to have varied between 20% to 28% wt zinc.[50] The high contentof zinc in coinage and brass objects declined after the first century AD and it has been suggested that this reflectszinc loss during recycling and thus an interruption in the production of new brass.[51] However it is now thought thiswas probably a deliberate change in composition[] and overall the use of brass increases over this period making uparound 40% of all copper alloys used in the Roman world by the 4th century AD.[52]

Brass making in the medieval period

Brass 7

Baptism of Christ on the 12th-century baptismal font at St Bartholomew's Church,Lige.

Little is known about the production ofbrass during the centuries immediately afterthe collapse of the Roman Empire.Disruption in the trade of tin for bronzefrom Western Europe may have contributedto the increasing popularity of brass in theeast and by the 6th7th centuries AD over90% of copper alloy artefacts from Egyptwere made of brass.[53] However otheralloys such as low tin bronze were also usedand they vary depending on local culturalattitudes, the purpose of the metal andaccess to zinc, especially between theIslamic and Byzantine world.[] Converselythe use of true brass seems to have declinedin Western Europe during this period in favour of gunmetals and other mixed alloys[54] but by the end of the firstMillennium AD brass artefacts are found in Scandinavian graves in Scotland,[55] brass was being used in themanufacture of coins in Northumbria[56] and there is archaeological and historical evidence for the production ofbrass in Germany[57] and The Low Countries[58] areas rich in calamine ore which would remain important centres ofbrass making throughout the medieval period,[59] especially Dinant brass objects are still collectively known asdinanterie in French. The baptismal font at St Bartholomew's Church, Lige in modern Belgium (before 1117) is anoutstanding masterpiece of Romanesque brass casting.

The cementation process continued to be used but literary sources from both Europe and the Islamic world seem todescribe variants of a higher temperature liquid process which took places in open-topped crucibles.[60] Islamiccementation seems to have used zinc oxide known as tutiya or tutty rather than zinc ores for brass making resultingin a metal with lower iron impurities.[61] A number of Islamic writers and the 13th century Italian Marco Polodescribe how this was obtained by sublimation from zinc ores and condensed onto clay or iron bars, archaeologicalexamples of which have been identified at Kush in Iran.[62] It could then be used for brass making or medicinalpurposes. In 10th century Yemen al-Hamdani described how spreading al-iglimiya, probably zinc oxide, onto thesurface of molten copper produced tutiya vapor which then reacted with the metal.[63] The 13th century Iranianwriter al-Kashani describes a more complex process whereby tutiya was mixed with raisins and gently roasted beforebeing added to the surface of the molten metal. A temporary lid was added at this point presumably to minimise theescape of zinc vapor.[64]

In Europe a similar liquid process in open-topped crucibles took place which was probably less efficient than theRoman process and the use of the term tutty by Albertus Magnus in the 13th century suggests influence from Islamictechnology.[65] The 12th century German monk Theophilus described how preheated crucibles were one sixth filledwith powdered calamine and charcoal then topped up with copper and charcoal before being melted, stirred thenfilled again. The final product was cast, then again melted with calamine. It has been suggested that this secondmelting may have taken place at a lower temperature to allow more zinc to be absorbed.[66] Albertus Magnus notedthat the "power" of both calamine and tutty could evaporate and described how the addition of powdered glass couldcreate a film to bind it to the metal.[67] German brass making crucibles are known from Dortmund dating to the 10thcentury AD and from Soest and Schwerte in Westphalia dating to around the 13th century confirm Theophilus'account, as they are open-topped, although ceramic discs from Soest may have served as loose lids which may havebeen used to reduce zinc evaporation, and have slag on the interior resulting from a liquid process.[68]

Brass 8

Brass making in Renaissance and post medieval EuropeThe Renaissance saw important changes to both the theory and practice of brassmaking in Europe. By the 15thcentury there is evidence for the renewed use of lidded cementation crucibles at Zwickau in Germany.[69] Theselarge crucibles were capable of producing c.20kg of brass.[70] There are traces of slag and pieces of metal on theinterior. Their irregular composition suggesting that this was a lower temperature not entirely liquid process.[71] Thecrucible lids had small holes which were blocked with clay plugs near the end of the process presumably tomaximise zinc absorption in the final stages.[72] Triangular crucibles were then used to melt the brass for casting.[73]

16th century technical writers such as Biringuccio, Ercker and Agricola described a variety of cementation brassmaking techniques and came closer to understanding the true nature of the process noting that copper becameheavier as it changed to brass and that it became more golden as additional calamine was added.[74] Zinc metal wasalso becoming more commonplace By 1513 metallic zinc ingots from India and China were arriving in London andpellets of zinc condensed in furnace flues at the Rammelsberg in Germany were exploited for cementation brassmaking from around 1550.[75]

Eventually it was discovered that metallic zinc could be alloyed with copper to make brass; a process known asspeltering[76] and by 1657 the German chemist Johann Glauber had recognised that calamine was "nothing else butunmeltable zinc" and that zinc was a "half ripe metal."[77] However some earlier high zinc, low iron brasses such asthe 1530 Wightman brass memorial plaque from England may have been made by alloying copper with zinc andinclude traces of cadmium similar those found in some zinc ingots from China.[76]

However the cementation process was not abandoned and as late as the early 19th century there are descriptions ofsolid state cementation in a domed furnace at around 900950 C and lasting up to 10 hours.[78] The European brassindustry continued to flourish into the post medieval period buoyed by innovations such as the 16th centuryintroduction of water powered hammers for the production of battery wares.[79] By 1559 the Germany city ofAachen alone was capable of producing 300,000 cwt of brass per year.[79] After several false starts during the 16thand 17th centuries the brass industry was also established in England taking advantage of abundant supplies of cheapcopper smelted in the new coal fired reverberatory furnace.[80] In 1723 Bristol brass maker Nehemiah Championpatented the use of granulated copper, produced by pouring molten metal into cold water.[81] This increased thesurface area of the copper helping it react and zinc contents of up to 33% wt were reported using this newtechnique.[82]

In 1738 Nehemiah's son William Champion patented a technique for the first industrial scale distillation of metalliczinc known as distillation per descencum or "the English process."[83][] This local zinc was used in speltering andallowed greater control over the zinc content of brass and the production of high zinc copper alloys which wouldhave been difficult or impossible to produce using cementation, for use in expensive objects such as scientificinstruments, clocks, brass buttons and costume jewellery.[84] However Champion continued to use the cheapercalamine cementation method to produce lower zinc brass[84] and the archaeological remains of bee-hive shapedcementation furnaces have been identified at his works at Warmley.[] By the mid-to-late 18th century developmentsin cheaper zinc distillation such as John-Jaques Dony's horizontal furnaces in Belgium and the reduction of tariffs onzinc[85] as well as demand for corrosion resistant high zinc alloys increased the popularity of speltering and as aresult cementation was largely abandoned by the mid-19th century.[86]

Brass 9

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Medicine[17] Copper Touch Surfaces. Congress Funds Testing of Copper's Ability to Kill Harmful Pathogens (http:/ / www. coppertouchsurfaces. org)[18] TouchSurfaces Clinical Trials: Research Proves (http:/ / www. coppertouchsurfaces. org/ press/ releases/ 20110701. html).

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2011[20] Michels, H.T., Wilks, S.A., Noyce, J.O., and Keevil, C.W., 2005, Copper Alloys for Human Infectious Disease Control, Materials Science

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on 2011-12-09.[24] manganese brass: Definition from (http:/ / www. answers. com/ topic/ manganese-brass). Answers.com. Retrieved on 2011-12-09.[27] Print Layout 1 (http:/ / www. aquafax. co. uk/ aquafax_v2/ html/ images/ aceimages/ TechData. pdf). (PDF) . Retrieved on 2011-12-09.[28] Thornton, C. P. (2007) "Of brass and bronze in prehistoric southwest Asia" in La Niece, S. Hook, D. and Craddock, P.T. (eds.) Metals and

mines: Studies in archaeometallurgy London: Archetype Publications. ISBN 1-904982-19-0[29] de Ruette, M. (1995) "From Contrefei and Speauter to Zinc: The development of the understanding of the nature of zinc and brass in Post

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[30][30] Cruden's Complete Concordance p. 55[31] Craddock, P.T. and Eckstein, K (2003) "Production of Brass in Antiquity by Direct Reduction" in Craddock, P.T. and Lang, J. (eds) Mining

and Metal Production Through the Ages London: British Museum pp. 2267[32] Rehren and Martinon Torres 2008, pp. 1705[33] Thornton 2007, pp. 189201[34][34] Craddock and Eckstein 2003 p. 217[35] Thornton, C.P and Ehlers, C.B. (2003) "Early Brass in the ancient Near East" in IAMS Newsletter 23 pp. 2736[36][36] Bayley 1990, p. 8[37][37] Rehren and Martinon Torres 2008, p. 169[38] Pliny the Elder Historia Naturalis XXXIV 2[39] Montero-Ruis, I and Perea, A (2007) "Brasses in the early metallurgy of the Iberian Peninsula" in La Niece, S. Hook, D. and Craddock, P.T.

(eds.) Metals and mines: Studies in archaeometallurgy London: Archetype: pp. 13640[40] Craddock and Eckstein 2003, pp. 2167[41][41] Craddock and Eckstein 2003, p. 217[42][42] Bayley 1990, p. 9[43] Craddock and Eckstein 2003, pp. 2224. Bayley 1990, p. 10.[44] Craddock, P.T. Burnett, A and Preston K. (1980) "Hellenistic copper-based coinage and the origins of brass" in Oddy, W.A. (ed) Scientific

Studies in Numismatics British Museum Occasional Papers 18 pp. 5364[45] Caley, E.R. (1964) Orichalcum and Related Ancient Alloys New York; American Numismatic Society

Brass 10

[46][46] Bayley 1990, p. 21[47] Rehren and Martinon Torres 2008, pp. 1701[48][48] Bayley 1990[49][49] Craddock and Eckstein 2003, p. 224[50][50] Craddock and Eckstein 2003, 224[51][51] Caley 1964[52][52] Craddock 1978, p. 14[53] Craddock, P.T. La Niece, S.C and Hook, D. (1990) "Brass in the Medieval Islamic World" in Craddock, P.T. (ed.) 2000 Years of Zinc and

Brass London: British Museum p. 73[54][54] Bayley 1990, p. 22[55] Eremin, K Graham-Campbell, J. and Wilthew, P. (2002) "Analysis of Copper alloy artefacts from Pagan Norse Graves in Scotland" in Biro,

K.T and Eremin, K. (eds) Proceedings of the 31st International Symposium on Archaeometry Oxford: Archaeopress BAR pp. 3429[56] Gilmore, G.R. and Metcalf, D.M (1980) "The alloy of the Northumbrian coinage in the mid-ninth century" in Metcalf, D and Oddy, W.

Metallurgy in Numismatics 1 pp. 8398[57][57] Rehren 1999[58] Day 1990, pp. 123150[59] Day 1990, pp. 12433[60] Craddock and Eckstein 2003, pp. 2245[61][61] Craddock et al 1990, 78[62] Craddock et al 1990, pp. 736[63][63] Craddock et al 1990, p. 75[64][64] Craddock et al 1990, p. 76[65] Rehren, T (1999) "The same...but different: A juxtaposition of Roman and Medieval brass making in Europe" in Young, S.M.M. (ed.)

Metals in antiquity Oxford: Archaeopress pp. 2527[66][66] Craddock and Eckstein 2003, 226[67] Rehren and Martinon Torres 2008, pp. 1768[68] Rehren and Martinon Torres 2008, pp. 1735[69] Martinon Torres and Rehren 2002, pp. 95111[70] Martinon Torres and Rehren 2002, pp. 1056[71][71] Martinon Torres and Rehren 2002, p. 103[72][72] Martinon Torres and Rehren 2002, p. 104[73][73] Martinon Torres and Rehren 2002, p. 100[74] Martinon Torres and Rehren 2008, 1812, de Ruette 1995[75][75] de Ruette 1995, 198[76][76] Craddock and Eckstein 2003, 228[77] de Ruette 1995, 1989[78] Craddock and Eckstein 2003, 2267.[79][79] Day 1990, p. 131[80] Day 1991, pp. 13544[81][81] Day 1990, p. 138[82][82] Craddock and Eckstein 2003, p. 227[83] Day 1991, pp. 17981[84][84] Day 1991, p. 183[85] Day 1991, pp. 1869[86] Day 1991, pp. 1923, Craddock and Eckstein 2003, p. 228

Bibliography Bayley, J. (1990) "The Production of Brass in Antiquity with Particular Reference to Roman Britain" in

Craddock, P.T. (ed.) 2000 Years of Zinc and Brass London: British Museum Craddock, P.T. and Eckstein, K (2003) "Production of Brass in Antiquity by Direct Reduction" in Craddock, P.T.

and Lang, J. (eds) Mining and Metal Production Through the Ages London: British Museum Day, J. (1990) "Brass and Zinc in Europe from the Middle Ages until the 19th century" in Craddock, P.T. (ed.)

2000 Years of Zinc and Brass London: British Museum Day, J (1991) "Copper, Zinc and Brass Production" in Day, J and Tylecote, R.F (eds) The Industrial Revolution in

Metals London: The Institute of Metals Martinon Torres, M. and Rehren, T. (2002). Historical Metallurgy 36 (2): 95111.

Brass 11

Rehren, T. and Martinon Torres, M. (2008) "Naturam ars imitate: European brassmaking between craft andscience" in Martinon-Torres, M and Rehren, T. (eds) Archaeology, History and Science Integrating Approaches toAncient Material: Left Coast Press

External links Brass.org (http:/ / www. brass. org)

Bronze

Bronze deer figurine dating from between the 9th and 6th centuriesBC, National Archaeological Museum of Sofia

Bronze is an alloy consisting primarily of copper,usually with tin as the main additive. It is hard andtough, and it was so significant in antiquity that theBronze Age was named after the metal. However,historical pieces were often made interchangeably ofbrasses (copper and zinc), and bronzes with differentcompositions, so modern museum and scholarlydescriptions of older objects increasingly use the moreinclusive term "copper alloy" instead.[1] Historically theterm latten was used for such alloys.

The word bronze (173040) is borrowed from Frenchbronze (1511), itself borrowed from Italian bronzo "bellmetal, brass" (13th century) (transcribed in MedievalLatin as bronzium), from either:

Ravenna *brntion, back-formation from ByzantineGreek brontson (11th century), perhaps fromBrentsion Brindisi, reputed for its bronze;[2][3] or

early Persian birinj, biranj () "brass" (modernberenj), piring () "copper",[4] from which alsocame Serbo-Croatian prina "brass",[5] Georgianbrinao "bronze", Armenian pinj "copper".

Bronze 12

History

Chinese Ding, Western Zhou (1046771 BC)

The discovery of bronze enabled people to create metal objectswhich were better than previously possible. Tools, weapons,armor, and various building materials, like decorative tiles, madeof bronze were harder and more durable than their stone andcopper ("Chalcolithic") predecessors. Initially bronze was madeout of copper and arsenic to form arsenic bronze, or directly fromnaturally or artificially mixed ores of those. It was only later thattin was used, becoming the sole type of major non-copperingredient of bronze in the late 3rd millennium BC. Tin bronzewas superior to arsenic bronze in that the alloying process itselfcould more easily be controlled and the alloy was stronger andeasier to cast. Also, unlike arsenic, tin is not toxic.

The earliest tin-alloy bronzes date to the late 4th millennium BC in Susa (Iran) and some ancient sites in China,Luristan (Iran) and Mesopotamia (Iraq).[citation needed]

Copper and tin ores are rarely found together (exceptions include one ancient site in Thailand and one in Iran), soserious bronze work has always involved trade. In Europe, the major source for tin was England's deposits of ore inCornwall, which were traded as far as Phoenicia in the Eastern Mediterranean.

Though bronze is generally harder than wrought iron, with Vickers hardness of 60258[6] vs. 3080,[7] the BronzeAge gave way to the Iron Age because iron was easier to find and to process into a poor grade of metal; although itcan be made into higher grades, doing that takes significantly more effort and skill. Bronze was still used during theIron Age. For example, officers in the Roman army had bronze swords[citation needed] while foot soldiers had iron;but, for many purposes, the weaker wrought iron was found to be sufficiently strong. Archaeologists suspect that aserious disruption of the tin trade precipitated the transition. The population migrations around 12001100 BCreduced the shipping of tin around the Mediterranean (and from Great Britain), limiting supplies and raising prices.[8]

Bianzhong of Marquis Yi of Zeng,Spring and Autumn Period (476221

BC)

As ironworking improved, iron became cheaper; and as cultures advanced fromwrought iron (typically forged by hand - wrought - by blacksmiths) to machineforged iron (typically made with trip hammers powered by water), they learnedhow to make steel, which is stronger than bronze and holds a sharper edgelonger.[9]

Bronze 13

Composition

A Bronze flag found in Iran, 3rd millennium BC

There are many different bronze alloys but modern bronze istypically 88% copper and 12% tin.[10] Alpha bronze consists ofthe alpha solid solution of tin in copper. Alpha bronze alloys of45% tin are used to make coins, springs, turbines and blades.Historical "bronzes" are highly variable in composition, as mostmetalworkers probably used whatever scrap was on hand; themetal of the 12th-century English Gloucester Candlestick isbronze containing a mixture of copper, zinc, tin, lead, nickel, iron,antimony, arsenic with 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 may suggest that the candlestickwas made from a hoard of old coins. The Benin Bronzes are reallybrass, and the Romanesque Baptismal font at St Bartholomew'sChurch, Lige is described as both bronze and brass.

Commercial bronze (90% copper and 10% zinc) andarchitectural bronze (57% copper, 3% lead, 40% zinc) are moreproperly regarded as brass alloys because they contain zinc as themain alloying ingredient. They are commonly used in architecturalapplications.[11][12]

Bismuth bronze is a bronze alloy with a composition of 52%copper, 30% nickel, 12% zinc, 5% lead, 1% bismuth. It is able to hold a good polish and so is sometimes used inlight reflectors and mirrors.[13]

Plastic bronze is bronze containing significant quantity of lead which makes for improved plasticity[14] possiblyused by the ancient Greeks in their ship construction.[15]

Other bronze alloys include aluminium bronze, phosphor bronze, manganese bronze, bell metal, arsenical bronze,speculum metal and cymbal alloys.

Properties

Assorted ancient bronze castings

Typically bronze only oxidizes superficially; once a copper oxide (eventuallybecoming copper carbonate) layer is formed, the underlying metal is protectedfrom further corrosion. However, if copper chlorides are formed, acorrosion-mode called "bronze disease" will eventually completely destroy it.[16]

Copper-based alloys have lower melting points than steel or iron, and are morereadily produced from their constituent metals. They are generally about 10percent heavier than steel, although alloys using aluminium or silicon may beslightly less dense. Bronzes are softer and weaker than steelbronze springs, forexample, are less stiff (and so store less energy) for the same bulk. Bronze resistscorrosion (especially seawater corrosion) and metal fatigue more than steel and isa better conductor of heat and electricity than most steels. The cost ofcopper-base alloys is generally higher than that of steels but lower than that ofnickel-base alloys.

Copper and its alloys have a huge variety of uses that reflect their versatile physical, mechanical, and chemical properties. Some common examples are the high electrical conductivity of pure copper, the low-friction properties of

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Bronze 14

bearing bronze, the resonant qualities of bell bronze, and the resistance to corrosion by sea water of several bronzealloys.The melting point of bronze varies depending on the ratio of the alloy components and is about 950 C (1,742F).Bronze may be nonmagnetic, but certain alloys containing iron or nickel may have magnetic properties.

Uses

Ewer from 7th-century Iran. Cast,chased, and inlaid bronze. New York

Metropolitan Museum of Art

Bronze was especially suitable for use in boat and ship fittings prior to the wideemployment of stainless steel owing to its combination of toughness andresistance to salt water corrosion. Bronze is still commonly used in shippropellers 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 incontemporary statuary. Sculptors may prefer silicon bronze because of the readyavailability of silicon bronze brazing rod, which allows color-matched repair ofdefects in castings. Aluminium is also used for the structural metal aluminiumbronze.

It is also widely used for cast bronze sculpture. Many common bronze alloyshave the unusual and very desirable property of expanding slightly just beforethey set, thus filling in the finest details of a mold. Bronze parts are tough andtypically used for bearings, clips, electrical connectors and springs.

Spring bronze weatherstripping comes in rolls of thin sheets and is nailed orstapled to wood windows and doors. There are two types, flat and v-strip. It hasbeen used for hundreds of years[citation needed] because it has low friction, sealswell and is long lasting. It is used in building restoration and customconstruction.

Bronze also has very low metal-on-metal friction, which made it invaluable for the building of cannon where ironcannonballs would otherwise stick in the barrel.[citation needed] It is still widely used today for springs, bearings,bushings, automobile transmission pilot bearings, and similar fittings, and is particularly common in the bearings ofsmall electric motors. Phosphor bronze is particularly suited to precision-grade bearings and springs. It is also usedin guitar and piano strings.

Unlike steel, bronze struck against a hard surface will not generate sparks, so it (along with beryllium copper) is usedto make hammers, mallets, wrenches and other durable tools to be used in explosive atmospheres or in the presenceof flammable vapors.Bronze is used to make bronze wool for woodworking applications where steel wool would discolor oak.

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Bronze 15

Bronze statuesIndian Hindu artisans from the period of the Chola empire in Tamil Nadu, used bronze to create intricate statues viathe lost wax casting method with ornate detailing depicting the Gods of Hinduism mostly, but also the lifestyle of theperiod. The art form survives to this day, with many silpis, craftsmen, working in the areas of Swamimalai andChennai.In antiquity other cultures also produced works of high art using bronze. For example: in Africa, the bronze heads ofthe Kingdom of Benin; in Europe, Grecian bronzes typically of figures from Greek mythology; in east Asia, Chinesebronzes 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.

Yoruba bronze head sculpture, Ife, Nigeria c.12th century AD

Musical instruments

Antique bell metal bronze singingbowls from the 16th to 18th

centuries. Annealed bronze continuesto be made in the Himalayas.

Bronze is the preferred metal for top-quality bells, particularly bell metal, whichis about 23% tin.

Nearly all professional cymbals are made from bronze, which gives a desirablebalance of durability and timbre. Several types of bronze are used, commonlyB20 bronze, which is roughly 20% tin, 80% copper, with traces of silver, or thetougher B8 bronze which is made from 8% tin and 92% copper. As the tincontent in a bell or cymbal rises, the timbre drops.[17]

Bronze is also used for the windings of steel and nylon strings of various stringedinstruments such as the double bass, piano, harpsichord, and the guitar. Bronzestrings are commonly reserved on pianoforte for the lower pitch tones, as theypossess a superior sustain quality to that of high-tensile steel.[18]

Bronzes of various metallurgical properties are widely used in struck idiophones around the world, notably bells,singing bowls, gongs, cymbals and other idiophones from Asia. Examples include Tibetan singing bowls, templebells of many sizes and shapes, gongs, Javanese gamelan and other bronze musical instruments. The earliest bronzearcheological finds in Indonesia date from 12 BCE, including flat plates probably suspended and struck by awooden or bone mallet.[18][19] Ancient bronze drums from Thailand and Vietnam date back 2,000 years. Bronzebells from Thailand and Cambodia date back to 3,600 BCE.

Bronze 16

Some companies are now making saxophones from phosphor bronze (3.5 to 10% tin and up to 1% phosphoruscontent). Bell Bronze is used to make the tone rings of many professional model banjos. The tone ring is a heavy(usually 3lbs.) folded or arched metal ring attached to a thick wood rim, over which a skin, or most often, a plasticmembrane (or head)is stretched-it is the bell bronze that gives the banjo a crisp powerful lower register and clear,bell-like treble register-especially in bluegrass music.

MedalsBronze has been used in the manufacture of various types of medals for centuries, and are known in contemporarytimes for being awarded to the second-runner up in sporting competitions and other events. The later usage was inpart attributed to the choices of gold, silver and bronze to represent the first three Ages of Man in Greek mythology:the Golden Age, when men lived among the gods; the Silver age, where youth lasted a hundred years; and theBronze Age, the era of heroes, and was first adopted at the 1904 Summer Olympics. At the 1896 event, silver wasawarded to winners and bronze to runners-up, while at 1900 other prizes were given, not medals.

References[1] British Museum, "Scope Note" for "copper alloy" (http:/ / www. britishmuseum. org/ research/ search_the_collection_database/ term_details.

aspx?scopeType=Terms& scopeId=18864). Britishmuseum.org. Retrieved on 2012-06-09.[2] Henry and Rene Kahane, "Byzantium's Impact on the West: The Linguistic Evidence", Illinois Classical Studies 06 (2) 1981, p. 395.[3] Originally M.P.E. Berthelot, "Sur le nom du bronze chez les alchimistes grecs", in Revue archologique, 1888, pp. 294-8.[4] Originally Karl Lokotsch, Etymologisches Wrterbuch der europischen Wrter orientalischen Ursprungs. (Heidelberg: Carl Winters

Universittsbuchhandlung, 1927), p. 1657.[5] Wolfgang Pfeifer, ed., Etymologisches Wrterbuch des Deutschen, s.v. Bronze (Munich: Deutscher Taschenbucher Vertrag, 2005).[6] Precious Metals: Bronze Jewelry (http:/ / www. allaboutgemstones. com/ metal_jewelry_bronze. html). Allaboutgemstones.com. Retrieved on

2012-06-09.[7] Smithells Metals Reference Book, 8th Edition, ch. 22[8] Clayton E. Cramer. What Caused The Iron Age? (http:/ / www. claytoncramer. com/ unpublished/ Iron2. pdf) claytoncramer.com. December

10, 1995[9] Oleg D. Sherby and Jeffrey Wadsworth. Ancient Blacksmiths, the Iron Age, Damascus Steels, and Modern Metallurgy (http:/ / www. llnl.

gov/ tid/ lof/ documents/ pdf/ 238547. pdf). Tbermec 2000, Las Vegas, Nevada December 48, 2000. Retrieved on 2012-06-09.[10] Knapp, Brian. (1996) Copper, Silver and Gold. Reed Library, Australia.[11] Copper alloys (http:/ / www. copper. org/ applications/ architecture/ arch_dhb/ copper_alloys/ intro. html). Copper.org (2010-08-25).

Retrieved on 2012-06-09.[12] CDA UNS Standard Designations for Wrought and Cast Copper and Copper Alloys: Introduction (http:/ / www. copper. org/ resources/

properties/ standard-designations/ introduction. html). Copper.org (2010-08-25). Retrieved on 2012-06-09.[13] Bismuth Bronze (http:/ / www. southerncrossmetalrecyclers. com. au/ scrap/ bismuth-bronze. html). Southerncrossmetalrecyclers.com.au.

Retrieved on 2012-06-09.[14] http:/ / encyclopedia2. thefreedictionary. com/ plastic+ bronze[15] http:/ / onlinelibrary. wiley. com/ doi/ 10. 1111/ 1095-9270. 12001/ full[16] Bronze Disease, Archaeologies of the Greek Past (http:/ / proteus. brown. edu/ greekpast/ 4867). Proteus.brown.edu. Retrieved on

2012-06-09.[18] McCreight, Tim. Metals technic: a collection of techniques for metalsmiths. Brynmorgen Press, 1992. ISBN 0-9615984-3-3[19] LaPlantz, David. Jewelry Metalwork 1991 Survey: Visions Concepts Communication: S. LaPlantz: 1991. ISBN 0-942002-05-9

Bronze 17

External links Bronze bells (http:/ / www. msm. cam. ac. uk/ phase-trans/ 2005/ bell/ bell. html) "Lost Wax, Found Bronze": lost-wax casting explained (http:/ / wildlifeart. org/ Foundry/ index2. html) "Flash animation of the lost-wax casting process" (http:/ / www. jepsculpture. com/ bronze. shtml). James

Peniston Sculpture. Retrieved 2008-11-03. Viking Bronze Ancient and Early Medieval bronze casting (http:/ / web. comhem. se/ vikingbronze/ )

Selective leachingSelective leaching, also called dealloying, demetalification, parting and selective corrosion, is a corrosion type insome solid solution alloys, when in suitable conditions a component of the alloys is preferentially leached from thematerial. The less noble metal is removed from the alloy by microscopic-scale galvanic corrosion mechanism. Themost susceptible alloys are the ones containing metals with high distance between each other in the galvanic series,e.g. copper and zinc in brass. The elements most typically undergoing selective removal are zinc, aluminium, iron,cobalt, chromium, and others.

Leaching of zincThe most common example is selective leaching of zinc from brass alloys containing more than 15% zinc(dezincification) in presence of oxygen and moisture, e.g. from brass taps in chlorine-containing water. It is believedthat both copper and zinc gradually dissolved out simultaneously and copper precipitates back from the solution. Thematerial remaining is a copper-rich sponge with poor mechanical properties, and color changed from yellow to red.Dezincification can be caused by water containing sulfur, carbon dioxide and oxygen. Stagnant or low velocitywaters tend to promote dezincification.To combat this, arsenic or tin can be added to brass, or gunmetal can be used instead. Dezincification resistantbrass (DZR) is an alloy used to make pipe fittings for use with potable water. Plumbing fittings that are resistant todezincification are appropriately marked, with the letters "CR" (Corrosion Resistant) or DZR (dezincificationresistant) in the UK, and the letters "DR" (dezincification resistant) in Australia.

Graphitic corrosion

Selective corrosion on cast iron. Magnification100x

Graphitic corrosion is selective leaching of iron from grey cast iron,where iron gets removed and graphite grains remain intact. Affectedsurfaces develop a layer of graphite, rust, and metallurgical impuritiesthat may inhibit further leaching. The effect can be substantiallyreduced by alloying the cast iron with nickel.[1]

Leaching of other elements

Dealuminification is a corresponding process for aluminum alloys.Similar effects for different metals are decarburization (removal ofcarbon from the surface of alloy), decobaltification, denickelification,etc.

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Selective leaching 18

Selective corrosion on cast iron. Magnification500x

Countermeasures

Countermeasures involve using alloys not susceptible to grainboundary depletion, using a suitable heat treatment, altering theenvironment (e.g. lowering oxygen content), and/or use cathodicprotection.

Uses

Selective leaching can be used to produce powdered materials withextremely high surface area, such as Raney nickel. Selective leachingcan be the pre-final stage of depletion gilding.

References[1] Don W. Green and James O. Maloney, eds. Perry's Chemical Engineers' Handbook. 7th ed., 1997.

External links Dezincification (http:/ / www. hghouston. com/ coppers/ brass75. htm)

Free machining steelFree machining steel is steel that forms small chips when machined. This increases the machinability of thematerial because smaller chips reduce the length of contact between the workpiece and the cutting tool, thusreducing friction, heat, power required, and wear on the tool. It also reduces the chance of chip entanglement. Freemachining steel costs 15 to 20% more than a standard steel, but this is made up by increased machining speeds,larger cuts, and longer tool life.[1]

The disadvantages of free machining steel are: ductility is decreased; impact resistance is reduced; copper-basedbrazed joints suffer from embrittlement with bismuth free machining grades; shrink fits are not as strong.[2]

TypesThere are four main types of free machining steel: leaded, resulfurized, rephosphorized and resulfurized, and super.Super free-machining steels are alloyed with tellurium, selenium, and bismuth.[]

Free machining steel 19

SAE steel grades for free-machining steel[]

Type SAE designation

Leaded 12L13

12L14

Rephosphorized and resulfurized 1211

1212

1213

Resulfurized 1117

1118

1119

MechanicsFree machining steels are carbon steels that have sulfur, lead, bismuth, selenium, tellurium, or phosphorus added.Sulfur forms the compound manganese sulfide, which is soft and acts as a chip-breaking discontinuity. It also acts asa dry lubricant to prevent a built up edge on the cutting tool. Lead works in a similar way to sulfur. Bismuth achievesa free machining steel by melting into a thin film of liquid for a fraction of a microsecond to lubricate the cut. Otheradvantages to bismuth include: more uniformly distributed because of its similar density to iron; moreenvironmentally friendly, as compared to lead; still weldable.[1]

References[1][1] Degarmo, p. 117.[2][2] Degarmo, p. 118.

Bibliography Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Manufacturing (9th ed.),

Wiley, ISBN0-471-65653-4.

Article Sources and Contributors 20

Article Sources and ContributorsBrass Source: http://en.wikipedia.org/w/index.php?oldid=553320214 Contributors: *drew, 129.132.139.xxx, 199.89.234.xxx, Abc518, Abductive, Aboalbiss, Acalamari, Acroterion,Addihockey10, AdjustShift, Adminix, Afv35, Alan Liefting, Alansohn, Alexdarkred, AlexiusHoratius, Ali, Aliza250, Alwolff55, Amazins490, Amillar, Anaraug, Andrewrp, Andy Dingley,Anetode, Areading, Ariel., Ariya shookh, Ash, AtheWeatherman, Aussie Alchemist, AutumnKent, Avant Guard, Avicennasis, Avoided, B.d.mills, Bantman, Bazonka, Beetstra, BenFrantzDale,Bentogoa, Biggishben, BillyPreset, Biscuittin, Blahblah743, Blanchardb, Bobblewik, Bobby4213, Bobo192, Bogey97, Bomb chelle, Bonadea, Bongwarrior, Boogaborg, Bryan Derksen,Bryancpark, Brycen, Bsadowski1, C.I 123, CLW, Calabe1992, CambridgeBayWeather, Can't sleep, clown will eat me, Canderson7, Cannibalicious!, Capricorn42, Cardtrick4, Carlsmith, Catgut,Chameleon, Chcastan, Chmee2, Chochopk, Chris the speller, ChrisGualtieri, ChrisHodgesUK, Christian75, Chugiak, Ck lostsword, Clark89, Closedmouth, Codex Sinaiticus, CommonsDelinker,Conversion script, Cordless Larry, Courcelles, Craigfry, Cricketgirl, Crisu, Crusoe8181, Cyde, D, DARTH SIDIOUS 2, DMacks, Dac04, Daniel.langkilde, Danjewell, Dcirovic, Deanj53,Deconstructhis, Deicas, Delldot, Deltabeignet, Deor, DetroitGrown, Dfrg.msc, Digitalme, Divyang.pandya, DocKrin, DocWatson42, Dominus, Dr Shorthair, Drilldoh, Dug0003, Dwolsten,Dysepsion, Dzubint, ECWAnna, ENeville, EWikist, Edwincruz654, Einstein9073, Elektrik Shoos, Ellieym, Elmschrat, Eloil, Entropy, Enviromet, Epbr123, Erl, Ernobe, Escape Orbit, Eubene,Everlast126, Everyking, Ewulp, Faizhaider, Fang1245, Favonian, FellGleaming, Femto, FengRail, Fortdj33, FourthAve, Frosted14, Fvasconcellos, Gaius Cornelius, Garamond Lethe, Gdr,Gentgeen, George Burgess, GideonF, Giftlite, Glenn, Glennled, Gogo Dodo, Goodnightmush, Grafen, Graham87, GrahamHardy, Graibeard, GreenSpigot, Guerrilla of the Renmin, HJ Mitchell,Haukurth, Hephaestus III, Heron, Hirenkhambhayta, Hobartimus, Homie.l, Htj213, Husond, Hut 8.5, Huw Powell, Hydrargyrum, IanMSpencer, IceCreamAntisocial, Im.a.lumberjack,IndulgentReader, Infinitelaughter, Ino5hiro, Intelligentsium, IronMaidenRocks, J heisenberg, J.delanoy, JDX, JForget, JPFen, Jackpotbox, Jahoe, James919, JamesBWatson, Jauhienij, Jayden54,Jdkessler, Jeffrey Mall, Jenenna, Jmlk17, John Carter, JohnCD, Johnbod, Johnhardcastl, Johnhardcastle, Johnlogic, Jojhutton, Jonik, Jose77, Jtmorgan, Jujutacular, Julesd, KDS4444,Kapilthakur79, Karada, Karelj, Karl Palmen, Keith D, Ketanashah, King Lopez, Kingpin13, Kirrages, Kjkolb, Kmg90, KnowledgeOfSelf, Kormoran, Krispos42, Kuru, Kvn8907, L Kensington,Leevclarke, Leszek Jaczuk, Leuko, Li1947, Liberal Classic, Lights, Ligulem, Lon of Oakdale, Lonicera, LouScheffer, MER-C, MONGO, Magioladitis, Malleus Fatuorum, Mariobro eh,MarkSutton, Markgalassi, Martin451, MartinezMD, Master Jay, Materialscientist, Matthiaswatkins, Mattjm, Mav, Maxis ftw, Mboverload, McAusten, McSly, Mejor Los Indios, Melaen, MelosAntropon, Metagraph, Miaow Miaow, Michael D L Marshall, Michael Greiner, Michael Hardy, Mkweise, Moe Epsilon, Monozigote, Moritz, Moyogo, Mr Morden76, Mrnaz, Mtze, N419BH,N5iln, Nabokov, Nanflaps, Naveen Sankar, NawlinWiki, Neelix, Neverquick, NewEnglandYankee, Nghia1991ad, Nickster4859, Nitroblu, Nmnogueira, Nsaa, Occamisation, Od Mishehu, OdaMari, Ollie, Oreo Priest, Orgelspielerkmd, Ozuma, PaterMcFly, PatrikR, Paulburnett, Peterlewis, Phaladone, Phantomsteve, Philip Trueman, Phdrus, Pinethicket, PlanetEditor, Plantsurfer,Plushpuffin, Pmj, Pmyteh, Poindexter Propellerhead, Poseidon1, Professor Chaos, Quadell, Qulix rules, Qwyrxian, R'n'B, RainbowOfLight, RandomCritic, RatnimSnave, Ray Van De Walker,Rees11, Rhobite, Robuckmetal, Rogermw, Rrostrom, Rusl, Ryanrs, SD43, Saeed1410, Saga City, Salmanazar, Samuelsen, Satellizer, SchnitzelMannGreek, SchroCat, Seaphoto, Shaddack,Shadowjams, Shadzar, Shawn in Montreal, Shervink, Shiggity, Shirik, Shogun, SilkTork, Silverchemist, Sir Cheesejawa the Magnificent, Skier Dude, Skizzik, Skunkboy74, Slsteffensen,Solipsist, Some jerk on the Internet, Sonett72, Spiel496, Spinach Dip, Splarka, Srleffler, StAnselm, Stan J Klimas, Stephen Gilbert, Stephenb, Stifynsemons, Stockdot, Strangerhahaha, T.defab,Tallasse, Tenmax, The High Fin Sperm Whale, The-world-is-dead12, Theseeker4, Thumperward, Tide rolls, Tom harrison, Tomwsulcer, Top8, Trevor MacInnis, Triadian, Twinsday,UberGranny, Ulric1313, Uncle Dick, Unionhawk, V.narsikar, VMS Mosaic, Valenciano, Veinor, Versageek, Versus22, Vishnu300, Vivacissamamente, Vsmith, WarthogDemon, Wavelength,Wifione, Wiki alf, Wikster E, William Avery, Willipod, Winchelsea, Wizard191, Wknight94, Woohookitty, Work permit, Wtmitchell, Xeno, Yamla, Yekrats, Youssefsan, Yuckfoo, YuckieDuck,Zeimusu, ZimZalaBim, ZooFari, , 857 anonymous edits

Bronze Source: http://en.wikipedia.org/w/index.php?oldid=555791922 Contributors: (jarbarf), 15autl1, 162.129.26.xxx, 9tmaxr, A More Perfect Onion, AV3000, Abductive, Acalamari, AdamBishop, Addshore, AdnanSa, Afroozpromethe, Ahoerstemeier, Alan561, Alansohn, Alborzagros, Aleenf1, All Classics Ltd, Alphachimp, Amazonien, Anbu121, Anders Torlind, Andre Engels,Andres, Andrewa, Ashishbhatnagar72, Astronautics, Aussie Alchemist, AxelBoldt, BD2412, Backyardbronze, Badagnani, Bastin, Bazonka, Bbpen, BeadleB, Beetstra, Benjah-bmm27, Bentogoa,BernardZ, Betacommand, Big.CountryH, Bilsonius, Biscuittin, Blee55, Bobo192, Bongwarrior, Bovineone, Brian Trotter, Brian0918, Bronze Kiwi, Brunnock, Bryan Derksen, Bryancpark, Bubbahotep, Can't sleep, clown will eat me, Carlsmith, Carolus, Chamaeleon, Cheverton, ChrisEich, ChrisHodgesUK, Chun-hian, Clicketyclack, Coastside, Colin Douglas Howell, Comet Tuttle,CommonsDelinker, Confuzion, Conversion script, Courcelles, Coyotedude, Cyde, DAFMM, DJ Clayworth, Dainis, Dakart, Dancarguy, Darekun, Darrendeng, Darrien, Darth Panda, Dbachmann,Ddode9, Deeptrivia, Deflective, Dekimasu, Delldot, Den fjttrade ankan, DerHexer, Dewrad, Dinak, Discospinster, DocWatson42, Doghunter226, Dominus, Doradus, Dragonbones, Drc79,Dtgriscom, Dycedarg, Dysepsion, E rulez, EEye, Edgar181, Efe, Egmontaz, Eranb, Ernobe, EryZ, Eshafto, Everyking, Excirial, FF2010, Fabiform, Faizhaider, Falconleaf, Fattyjwoods,Feeeshboy, Femto, FengRail, Ferrarimangp, FiP, Fieari, Fieldday-sunday, Fitzed, Florian Blaschke, Flyguy649, Fourier5, FourthAve, Frankie1969, F, Gaff, Gaius Cornelius, Gdarin,Geneb1955, Gilliam, Glenn, Godfrey Daniel, Gogo Dodo, Gopher65, Graham87, Graibeard, GreatWhiteNortherner, GregAsche, Gregors, Gregory Benoit, Grm wnr, Groyolo, Guaca, Guerrilla ofthe Renmin, HJJHolm, Ham7girl, Harman khaira40, Hashar, HereToHelp, Huaiwei, Hydrargyrum, IChentsov, Icairns, Imz97, Inniverse, Iroony, Isnow, Ixfd64, J.delanoy, Jafd88, Jake-helliwell,Jamesday, Jason Quinn, Jauhienij, JayTau, Jeff G., Jersey emt, Jiddisch, Jimgawn, Jivecat, Jll294, Joefromrandb, Joeynthk, John, Johnbod, Johnhardcastl, Johnhardcastle, Jojhutton, Jose77,Jrdioko, Jschnur, Jstupple7, Jurema Oliveira, Jurohi, Katalaveno, Keith Edkins, Ketanashah, Kevin Ryde, Kingpin13, Kjkolb, Kormoran, Kubigula, KudzuVine, Kukini, Kungfuadam, Kyriosity,LAlawMedMBA, Lawsuits, LedgendGamer, Legacybronze, Legoman55, Leolaursen, Leonard G., Leuko, Lexicon, Lg king, LibLord, Libertines, Lightmouse, Ling.Nut, Louisl7, Luckharry,Lugnuts, MPerel, Madhero88, Magister Mathematicae, Mandarax, Marek69, Marinepower, Mark, MarkTwainOnIce, Markashdown, Markkawika, Master Jay, Materialscientist, Matty4123,Maury Markowitz, Mblumber, McFarty, Mconst, Mhartl, Mic, Michael Hardy, Mike Dillon, Mike Rosoft, Mike1942f, Mikeo, Mikko Paananen, Misza13, Moe Epsilon, Monozigote,Moosepucky, Mordicai, MrOllie, Mrnaz, Mrrhum, Myasuda, Myfilthyballsack, N419BH, Nabokov, Nakon, Narasimhavarman10, NathanHurst, Neo-Jay, NerdyScienceDude, New England,Nielhodson, Nightkey, Nima.nezafati, Ning-ning, Nono64, Norm mit, Northumbrian, Nrlawver, O.Koslowski, Ocanter, OffsBlink, Ohnoitsjamie, Ojigiri, Orestek, PMLawrence, PRRfan,PTOmac, Pakb'u, Paul August, Pax:Vobiscum, PericlesofAthens, Peter Isotalo, Philip Trueman, Pichpich, PinchasC, Pinethicket, Piotrus, Pixelface, Plantsurfer, PlasticPassion, Poli, ProximaCentauri, PsuedoName, Qxz, RL0919, RLC Davidson, RTBoyce, Ranveig, Rbeas, Redrose64, ReignMan, Research Method, RexNL, Richard Arthur Norton (1958- ), Richard75, Rjwilmsi,Rklawton, Romanm, Ronhjones, Rrostrom, Rursus, Rusl, Ruy Pugliesi, Samw, Saperaud, SchfiftyThree, SchreiberBike, Sean William, SeanWillard, Securiger, Sgdavis107, Shaddack,Shaheenjim, ShelfSkewed, Shezzinator, Shisock, Siafu, SidP, Silivrenion, Simetrical, Sinus, SkerHawx, Slappy21, Slysplace, Smack, Snow Blizzard, Somnior, Sonett72, Sphery, SpikeToronto,Spinningspark, Squids and Chips, Srajan01, Starstylers, Stephenb, StevenDC, Subversive.sound, Sunilthombre, Super-Magician, THEN WHO WAS PHONE?, Taed, Tagishsimon, Tarquin,Techman224, TheDragoon, TheLeopard, Theseeker4, Thumperward, Tide rolls, Titoxd, Tnxman307, Tom harrison, Tony Sidaway, Tonymartin, Torvalu4, Tourbillon, Tullie, Tximist, Ukabia,Ummit, Un chien andalou, Unnecessary, Unschool, Utcursch, UtherSRG, V.narsikar, V111P, Van helsing, Vatsalyachugh, Velho, Vibeway, Victoriaedwards, Violask81976, Vrenator, Vsmith,Waltpohl, Waycool27, Wfaxon, Why Not A Duck, Widr, William Avery, Willking1979, Wimt, Winchelsea, Windchaser, Wisq, Wizard191, Wknight94, Woohookitty, Wyss, Xevi, Xiahou,Xymmax, Yandman, Yeungkinglun, Yintan, YoungBronze, Ytrottier, Yurik, Zalgo, Zereshk, ZooFari, ZxxZxxZ, 762 anonymous edits

Selective leaching Source: http://en.wikipedia.org/w/index.php?oldid=551955979 Contributors: A876, BD2412, Bender235, Biscuittin, Kjkolb, Occamisation, Prari, Robert Treat, Rodsan18,Rogerzilla, Shaddack, Stan J Klimas, 3 anonymous edits

Free machining steel Source: http://en.wikipedia.org/w/index.php?oldid=540513403 Contributors: Kragen, Mchl, Squids and Chips, Vogelfrey, Wizard191, 2 anonymous edits

Image Sources, Licenses and Contributors 21

Image Sources, Licenses and ContributorsFile:Brass.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Brass.jpg License: Public Domain Contributors: Drilnoth, Ies, Juiced lemon, Maksim, Mindmatrix, Ra'ike, WstFile:Macrostructure of rolled and annealed brass; magnification 400X.jpg Source:http://en.wikipedia.org/w/index.php?title=File:Macrostructure_of_rolled_and_annealed_brass;_magnification_400X.jpg License: Public Domain Contributors: StrangerhahahaFile:00 BMA Automation Sampling cock.JPG Source: http://en.wikipedia.org/w/index.php?title=File:00_BMA_Automation_Sampling_cock.JPG License: Creative CommonsAttribution-Sharealike 3.0 Contributors: ElmschratFile:BrassSCC1.jpg Source: http://en.wikipedia.org/w/index.php?title=File:BrassSCC1.jpg License: Public Domain Contributors: Daniele Pugliesi, PadawaneFile:Renier de Huy JPG0.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Renier_de_Huy_JPG0.jpg License: Creative Commons Attribution 2.5 Contributors: Jean-PolGRANDMONTFile:National Archaeological Museum Sofia - 3,000 Years Old Bronze Dear.jpg Source:http://en.wikipedia.org/w/index.php?title=File:National_Archaeological_Museum_Sofia_-_3,000_Years_Old_Bronze_Dear.jpg License: Creative Commons Attribution 2.0 Contributors: AnnWuytsFile:Defang Ding.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Defang_Ding.jpg License: GNU Free Documentation License Contributors: BrokenSphere, Cold Season, Hiart,Kanguole, Lilyu, Mountain, Petropoxy (Lithoderm Proxy), 2 anonymous editsFile:Bianzhong.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Bianzhong.jpg License: GNU Free Documentation License Contributors: Original uploader was Zzjgbc atzh.wikipediaFile:Bronze flag, Shadad Kerman, Iran.JPG Source: http://en.wikipedia.org/w/index.php?title=File:Bronze_flag,_Shadad_Kerman,_Iran.JPG License: Public Domain Contributors:Alborzagros, 1 anonymous editsFile:Assorted bronze castings.JPG Source: http://en.wikipedia.org/w/index.php?title=File:Assorted_bronze_castings.JPG License: Public Domain Contributors: Gaius Cornelius, Glenn, Ies,Mercurywoodrose, TimTay, Winterkind, 4 anonymous editsFile:Early Ewer Iran.JPG Source: http://en.wikipedia.org/w/index.php?title=File:Early_Ewer_Iran.JPG License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:ZereshkImage:Yoruba-bronze-head.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Yoruba-bronze-head.jpg License: Public Domain Contributors: WaynaQhapaqFile:Picsingingbowls.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Picsingingbowls.jpg License: GNU Free Documentation License Contributors: en:User:JfinsfFile:Spongiose100.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Spongiose100.jpg License: GNU Free Documentation License Contributors: Ies, Ra'ike, berraschungsbilderFile:Spongiose500.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Spongiose500.jpg License: GNU Free Documentation License Contributors: Ies, Ra'ike, berraschungsbilder

License 22

LicenseCreative Commons Attribution-Share Alike 3.0 Unported//creativecommons.org/licenses/by-sa/3.0/