Editing Welding (section)

==History==
[[Image:QtubIronPillar.JPG|thumb|The iron pillar of Delhi, India]]

The history of joining metals goes back several millennia.<ref>{{harvnb|"History of Metal"|2020}}</ref> [[Fusion welding]] processes that join metals by melting them were not widely used in [[Pre-industrial society|pre-industrial]] welding. Early welding techniques used pressure to join to the metals, often with heat not sufficient to fully melt the base metals.<ref>{{harvnb|Maryon|1949|pp=102-103}}</ref> One notable exception was a technique to join sections of large statues. In Greek and Roman [[lost-wax casting]], the statues were cast as smaller pieces and molten bronze was poured into the joints with temperatures sufficient to create fusion welds.<ref>{{harvnb|Azéma|Mille|Echégut|Meneses|2011|pp=71–80}}</ref>

The earliest known welding dates to the [[Bronze Age]]. Gold is soft enough to be pressure welded with little to no heat, and archaeologists have found small boxes made by pressure welding overlapping sheets of gold. In the [[Iron Age]], Mediterranean societies developed [[forge welding]].<ref>{{harvnb|Cary|Helzer|2005|p=4}}</ref> In forge welding, metal is heated to the point that it becomes soft enough for a [[blacksmith]] to hammer separate pieces together.<ref>{{harvnb|Maryon|1949|p=103}}</ref> Very early notable examples are the [[Tutankhamun's meteoric iron dagger|iron objects found with Tutankhamun]] including an iron headrest and dagger.<ref>{{harvnb|Maryon|1949|p=103}}</ref><ref>{{harvnb|Matsui|Moriwaki|Zidan|Arai|2022|pp=}}</ref> The dagger was forged from [[meteoric iron]] at temperatures below {{convert|950|C}}.<ref>{{harvnb|Matsui|Moriwaki|Zidan|Arai|2022|pp=}}</ref> Typically, [[wrought iron]] is forged at around {{convert|1350|C}}.<ref>{{harvnb|Khurmi|Gupta|2008|p=275}}</ref> The ancient Greek historian [[Herodotus]] credits [[Glaucus of Chios]] with discovering "iron welding".<ref>{{harvnb|Greenewalt|Heywood|1992|p=24}}, iron "''κόλλησις''" or "kollisis"; {{harvnb|"Archaeological Discussions"|1901|p=460}}</ref> Glaucus is known for an iron pedestal welded to hold a silver [[krater]] at [[Delphi]].<ref>{{harvnb|Whitehouse|1989|p=120}}</ref>

[[File:Welding the Big Ring - Westinghouse Works.webm|thumb|[[Forge welding]] in 1904<ref>{{cite AV media |url=https://www.loc.gov/item/96522219 |title=Welding the Big Ring |publisher=American Mutoscope and Biograph Company |location=United States |date=1904 |last1=Bitzer |first1=G.W. |series=Westinghouse Works}}</ref>]]

The [[Middle Ages]] brought advances in [[forge welding]], in which blacksmiths pounded heated metal repeatedly until bonding occurred.<ref name="LE111" /> In Europe and Africa, forging shifted from open charcoal fires to [[bloomery|bloomeries]]. China developed the [[blast furnace]] late in the first millennia.<ref>{{harvnb|"Iron History"|2020}}</ref> Forge welding was used in the construction of the [[Iron pillar of Delhi]], erected in [[Delhi]], India about 310 AD and weighing 5.4&nbsp;[[metric tons]].<ref>{{harvnb|Cary|Helzer|2005|p=4}}</ref> In 1540, [[Vannoccio Biringuccio]] published ''[[De la pirotechnia]]'', which includes descriptions of the forging operation.<ref name="LE111">{{harvnb|Lincoln Electric|1994|p=1.1-1}}</ref> [[Renaissance]] craftsmen were skilled in the process, and the industry continued to grow during the following centuries.<ref name="LE111" />

In 1800, [[Humphry Davy|Sir Humphry Davy]] discovered the short-pulse electrical arc and presented his results in 1801.<ref>{{harvnb|Lincoln Electric|1994|p=1.1-1}}<!--hyphenated page! Not a range.--></ref><ref name="Ayrton">{{harvnb|Ayrton|1902|pp=20, 24, 94}}</ref><ref name="anders">{{harvnb|Anders|2003|pp=1060-1069}}</ref> In 1802, Russian scientist [[Vasily Vladimirovich Petrov|Vasily Petrov]] created the continuous electric arc,<ref name="anders" /><ref>[[Great Soviet Encyclopedia]], Article ''"Дуговой разряд"'' (eng. ''electric arc'')</ref><ref>{{Citation |last=Lazarev |first=P.P. |title=Historical Essay on the 200 Years of the Development of Natural Sciences in Russia |journal=[[Physics-Uspekhi]] |volume=42 |issue=1247 |pages=1351–1361 |date=December 1999 |url=http://ufn.ru/ufn99/ufn99_12/Russian/r9912h.pdf |format=Russian |archive-url=https://web.archive.org/web/20110211173732/http://ufn.ru/ufn99/ufn99_12/Russian/r9912h.pdf |archive-date=2011-02-11 |doi=10.1070/PU1999v042n12ABEH000750 |s2cid=250892442 |url-status=dead}}</ref> and subsequently published "News of Galvanic-Voltaic Experiments" in 1803, in which he described experiments carried out in 1802. Of great importance in this work was the description of a stable arc discharge and the indication of its possible use for many applications, one being melting metals.<ref name="biog1">{{cite encyclopedia |title=Complete Dictionary of Scientific Biography |url=http://www.encyclopedia.com/doc/1G2-2830903379.html |date=2008 |encyclopedia=Encyclopedia.com |publisher=Charles Scribner's Sons |access-date=9 October 2014}}</ref> In 1808, Davy, who was unaware of Petrov's work, rediscovered the continuous electric arc.<ref name="Ayrton" /><ref name="anders" /> In 1881–82 inventors [[Nikolai Benardos]] (Russian) and [[Stanisław Olszewski]] (Polish)<ref>{{ cite patent |invent1=Nikołaj Benardos |invent2=Stanisław Olszewski |title=Process of and apparatus for working metals by the direct application of the electric current |number=363,320 |gdate=1887-05-17 |country=US |url=https://patentimages.storage.googleapis.com/74/6f/2a/17ed495adeac02/US363320.pdf}}</ref> created the first electric arc welding method known as [[carbon arc welding]] using carbon electrodes. The advances in arc welding continued with the invention of metal electrodes in the late 1800s by a Russian, [[Nikolai Slavyanov]] (1888), and an American, [[C. L. Coffin]] (1890). Around 1900, A. P. Strohmenger released a coated metal electrode in [[United Kingdom|Britain]], which gave a more stable arc. In 1905, Russian scientist Vladimir Mitkevich proposed using a three-phase electric arc for welding. [[Alternating current]] welding was invented by C. J. Holslag in 1919, but did not become popular for another decade.<ref>{{harvnb|Cary|Helzer|2005|pp=5–6}}</ref>

[[Resistance welding]] was also developed during the final decades of the 19th century, with the first patents going to [[Elihu Thomson]] in 1885, who produced further advances over the next 15 years. [[Thermite welding]] was invented in 1893, and around that time another process, [[oxyfuel welding]], became well established. [[Acetylene]] was discovered in 1836 by [[Edmund Davy]], but its use was not practical in welding until about 1900, when a suitable [[gas welding#Torch|torch]] was developed.<ref>{{harvnb|Cary|Helzer|2005|p=6}}</ref> At first, oxyfuel welding was one of the more popular welding methods due to its portability and relatively low cost. As the 20th century progressed, however, it fell out of favor for industrial applications. It was largely replaced with arc welding, as advances in metal coverings (known as [[flux (metallurgy)|flux]]) were made.<ref name="Weman26">{{harvnb|Weman|2003|p=26}}</ref> Flux covering the electrode primarily shields the base material from impurities, but also stabilizes the arc and can add alloying components to the weld metal.<ref name='ESAB'>{{cite web |title=Lesson 3: Covered Electrodes for Welding Mild Steels |url=http://www.esabna.com/euweb/awtc/lesson3_6.htm |access-date=18 May 2017}}</ref>

[[File:Acetylene welding on cylinder water jacket., 1918 - NARA - 530779.jpg|thumb|left|170px|Acetylene welding on cylinder water jacket, US Army 1918]]
World War I caused a major surge in the use of welding, with the various military powers attempting to determine which of the several new welding processes would be best.<ref>{{harvnb|Albloushi|Albloushi|2019|p=33}}</ref> The British primarily used arc welding, even constructing a ship, the "Fullagar" with an entirely welded hull.<ref name="Sapp-1900-1950">{{harvnb|Sapp|2012|loc=1900-1950}}</ref><ref>{{Cite magazine |title=Cammellaird-Fullagar Diesel Engine - (No. II) |pages=132–144 |magazine=The Engineer |date=6 February 1920 |author=((Cammell, Laird and Co.)) |url=https://www.gracesguide.co.uk/The_Engineer_1920/02/06 |via=Grace's Guide to British Industrial History}}</ref>{{rp|142}} Arc welding was first applied to aircraft during the war as well, as some German airplane fuselages were constructed using the process.<ref>{{harvnb|Lincoln Electric|1994|p=1.1–5}}</ref>

During the middle of the century, many new welding methods were invented, including the introduction of automatic welding in 1920, in which electrode wire was fed continuously.<ref>{{harvnb|Cary|Helzer|2005|p=7}}</ref> [[Shielding gas]] received much attention, as scientists attempted to protect welds from the effects of oxygen and nitrogen in the atmosphere. Porosity and brittleness were the primary problems, and the solutions that developed included the use of [[hydrogen]], [[argon]], and [[helium]] as welding atmospheres.<ref>{{harvnb|Cary|Helzer|2005|p=7}}</ref> Testing methods were introduced for weld integrity. First vibration testing was done using a hammer and [[stethoscope]]; later, [[X-ray]] tests were developed to see into the weld.<ref>{{harvnb|Irving|1999|pp=61-64}}</ref> During the 1930s, further advances allowed for the welding of reactive metals like [[aluminium|aluminum]] and [[magnesium]].<ref>{{harvnb|Lincoln Electric|1994|p=1.1–6}}</ref> This in conjunction with developments in automatic welding, alternating current, and fluxes fed a major expansion of arc welding during the 1930s.<ref>{{harvnb|Lincoln Electric|1994|p=1.1–6}}</ref> Russian inventor [[Konstantin Khrenov]] implemented the first underwater electric arc welding.<ref>{{harvnb|Cary|Helzer|2005|p=9}}</ref> In 1930, Kyle Taylor was responsible for the release of [[stud welding]], which soon became popular in shipbuilding and construction. [[Submerged arc welding]] was invented the same year.<ref>{{harvnb|Cary|Helzer|2005|p=9}}</ref> During World War II, submerged arc welding was widely used for ship-building because it allowed certain types of welds to be done twenty times faster than earlier techniques.<ref>{{harvnb|Irving|1999|pp=61-64}}</ref>

[[Image:Maurzyce 2009 (0).jpg|thumb|Bridge of Maurzyce]]

Improvements to welding processes opened up new possibilities for construction.<ref>{{harvnb|Irving|1999|pp=61-64}}</ref> Previously, large metal structures had been made from metals joined mechanically with rivets, along with bolts, screws, and belts. These connected but unfused metal structures had inherent weaknesses.<ref>{{harvnb|Voynick|1998|p=178}}</ref> The steamboat ''[[Sultana (steamboat)|Sultana]]'' killed over a thousand passengers when its riveted boiler failed under pressure.<ref>{{harvnb|Irving|1999|pp=61-64}}</ref> The "unsinkable" ''[[Titanic]]'' sank due in part to failures in its riveted hull.<ref>{{harvnb|Voynick|1998|p=178}}</ref> In 1930, the first all-welded merchant vessel, [[M/S Carolinian|M/S ''Carolinian'']], was launched.<ref>{{Cite magazine |date=1930-03-17 |title=Science: Welded Steamer |url=https://content.time.com/time/subscriber/article/0,33009,738850,00.html |magazine=Time |language=en-US |issn=0040-781X}}</ref> The strength of welded steel also allowed for the creation of entirely new types of ships, notably the [[LNG carrier|liquefied natural gas (LNG) tanker]]. The [[ASME Boiler and Pressure Vessel Code]], created in response to deadly boiler failures was used to develop the spherical tanks that contain LNG during transport.<ref>{{harvnb|Irving|1999|pp=61-64}}</ref> Also noteworthy is the first welded road bridge in the world, the [[Maurzyce Bridge]] in Poland (1928).<ref name="Sapp-1900-1950"/> Early skyscrapers and [[truss bridge|steel truss bridges]] were built from riveted steel beams.<ref>{{harvnb|Voynick|1998|p=178}}</ref><ref>{{harvnb|Sieber|Urbanek|Bär|2019|loc=sec. 1.1}}</ref> Welding allows for stronger and lighter structures and greater range of shapes.<ref>{{cite web |title=Welding in Architecture: Why It Matters - The Welding Academy |url=https://weldingacademy.co.nz/blog/welding-in-architecture-why-it-matters/ |website=Welding Academy |date=17 October 2023}}</ref> The [[Sydney Opera House]]'s icon shape is built on a stud-welded steel frame.<ref>{{cite web |title=4 Famous Landmarks that Used Structural Steel Welding in Their Construction |url=https://norfas.com/famous-landmarks-used-structural-steel-welding/ |website=Northland |date=28 April 2020}}</ref>

[[File: Portable welder Sydney Water Photograph Collection A-00069901.tif|thumb|Portable welder being used for Sydney stormwater infrastructure]] 

[[Gas tungsten arc welding]], after decades of development, was finally perfected in 1941, and gas metal arc welding followed in 1948, allowing for fast welding of non-[[ferrous]] materials but requiring expensive shielding gases. Shielded metal arc welding was developed during the 1950s, using a flux-coated consumable electrode, and it quickly became the most popular metal arc welding process. In 1957, the flux-cored arc welding process debuted, in which the self-shielded wire electrode could be used with automatic equipment, resulting in greatly increased welding speeds, and that same year, [[plasma arc welding]] was invented by Robert Gage. Electroslag welding was introduced in 1958, and it was followed by its cousin, [[electrogas welding]], in 1961.<ref>{{harvnb|Cary|Helzer|2005|p=9}}</ref> In 1953, the Soviet scientist N. F. Kazakov proposed the [[diffusion welding|diffusion bonding]] method.<ref>{{cite web |url=http://www.msm.cam.ac.uk/phase-trans/2005/Amir/bond.html |title=Diffusion Bonding of Materials |last=Kazakov |first=N.F |year=1985 |publisher=University of Cambridge |access-date=2011-01-13 |url-status=dead |archive-url=https://web.archive.org/web/20130901221424/http://www.msm.cam.ac.uk/phase-trans/2005/Amir/bond.html |archive-date=2013-09-01}}</ref>

Other recent developments in welding include the 1958 breakthrough of electron beam welding, making deep and narrow welding possible through the concentrated heat source. Following the invention of the laser in 1960, laser beam welding debuted several decades later, and has proved to be especially useful in high-speed, automated welding. [[Magnetic pulse welding]] (MPW) has been industrially used since 1967. [[Friction stir welding]] was invented in 1991 by Wayne Thomas at [[The Welding Institute]] (TWI, UK) and found high-quality applications all over the world.<ref>{{cite book |author=Mel Schwartz |title=Innovations in Materials Manufacturing, Fabrication, and Environmental Safety |url=https://books.google.com/books?id=rpCs0AoQOBoC&pg=PA300 |date=2011 |publisher=CRC Press |isbn=978-1-4200-8215-9 |page=300}}</ref> All of these four new processes continue to be quite expensive due to the high cost of the necessary equipment, and this has limited their applications.<ref>{{harvnb|Lincoln Electric|1994|pp=1.1–10}}</ref>