NationMaster - Encyclopedia: Arc welding

Arc welding uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and/or an evaporating filler material. The process of arc welding is widely used because of its low capital and running costs. Image File history File linksMetadata Download high resolution version (1960x2213, 3402 KB) A man gas metal arc welding. ... Image File history File linksMetadata Download high resolution version (1960x2213, 3402 KB) A man gas metal arc welding. ... Gas metal arc welding Gas metal arc welding (GMAW), sometimes referred to by its subtypes, metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through... A high output constant current welding power supply for use with GTAW and SMAW A welding power supply is an electrical device that provides an electrical current to perform welding procedures which require electricity. ... Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, similar to the instant spark, resulting from a current flowing through normally nonconductive media such as air. ... Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ... City lights viewed in a motion blurred exposure. ... An electrode is an electrical conductor used to make contact with a metallic part of a circuit (e. ... An inert gas is any gas that is not reactive under normal circumstances. ... Shielding gases are inert or semi-inert gases that are commonly used in several welding processes, most notably gas metal arc welding and gas tungsten arc welding. ...

Development

While examples of forge welding go back to the Bronze Age and the Iron Age, arc welding did not come into practice until much later. In 1800, Humphry Davy discovered the electric arc, initiating the development of arc welding which continued with the inventions of metal electrodes by a Russian (N.G. Slavianoff) and an American (C.L. Coffin) in the late 1800s even as carbon arc welding, which used a carbon electrode, gained popularity. Around 1900, A. P. Strohmenger released in Britain a coated metal electrode which gave a more stable arc. In 1919, alternating current welding was invented by C.J. Holslag but did not become popular for another decade. Forge welding is a welding process of heating two or more pieces of wrought iron or steel until their surfaces are malleable and then hammering them together. ... The Bronze Age is a period in a civilizations development when the most advanced metalworking has developed the techniques of smelting copper from natural outcroppings and alloys it to cast bronze. ... Iron Age Axe found on Gotland This article is about the archaeological period known as the Iron Age, for the mythological Iron Age see Iron Age (mythology). ... Sir Humphry Davy, 1st Baronet, FRS (17 December 1778 â€“ 29 May 1829) was a British chemist and physicist. ... Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, similar to the instant spark, resulting from a current flowing through normally nonconductive media such as air. ... Carbon Arc Welding (CAW) is a process in which an arc is established between a nonconsumable carbon (graphite) electrode and the work, or between two carbon electrodes. ... General Name, symbol, number carbon, C, 6 Chemical series nonmetals Group, period, block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... City lights viewed in a motion blurred exposure. ...

Competing welding processes such as resistance welding and oxyfuel welding were developed during this time as well, but both, especially the latter, faced stiff competition from arc welding especially after metal coverings (known as flux) for the electrode, to stabilize the arc and shield the base material from impurities, continued to be developed. During the surge in the use of welding caused by World War I, arc welding became even more popular as the British constructed a ship, the Fulagar, with an entirely welded hull. The Americans also became more accepting of the new technology when the process allowed them to repair their ships quickly after a German attack in the New York Harbor at the beginning of the war. Arc welding was first applied to aircraft during the war as well, and some German airplane fuselages were constructed using this process. Resistance welding refers to a group of welding processes that produce coalescence of the faying surfaces with the heat obtained from resistance of the workpieces to the flow of the welding current in a circuit of which the workpieces are part, and by the application of pressure. ... Compressed gas cylinders containing oxygen and MAPP gas. ... In metallurgy, flux is a substance which removes passivating oxides from the surface of a metal or alloy. ... â€œThe Great War â€ redirects here. ... New York Harbor, a geographic term, refers collectively to the rivers, bays, and tidal estuaries near the mouth of the Hudson River in the vicinity of New York City. ...

During the 1920s, major advances were made in welding technology, including the 1920 introduction of automatic welding in which electrode wire was continuously fed. Shielding gas became a subject receiving 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. During the following decade, further advances allowed for the welding of reactive metals such as aluminum and magnesium. This, in conjunction with developments in automatic welding, alternating current, and fluxes fed a major expansion of arc welding during the 1930s and then during World War II. Shielding gases are inert or semi-inert gases that are commonly used in several welding processes, most notably gas metal arc welding and gas tungsten arc welding. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Standard atomic weight 39. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Standard atomic weight 4. ... Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki TÅjÅ Casualties Military dead: 17,000,000 Civilian dead: 33,000...

During the middle of the century, many new welding methods were invented. Submerged arc welding was invented in 1930 and continues to be popular today. 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. Using a consumable electrode and a carbon dioxide atmosphere as a shielding gas, 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. In that same year, plasma arc welding was invented. Electroslag welding was released in 1958 and was followed by its cousin, electrogas welding, in 1961. A submerged arc welder used for training. ... Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. ... Gas metal arc welding Gas metal arc welding (GMAW), sometimes referred to by its subtypes, metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through... Ferrous in chemistry is a term used for the iron with an oxidation number +2. ... In order to meet Wikipedias quality standards, this article requires cleanup. ... A wire feeder configured for . ... Plasma arc welding (PAW) is an extension of the gas tungsten arc welding (GTAW) process. ... Electroslag welding is a highly productive welding process developed in the United States during the 1930s. ... Electrogas welding (EGW) is a continuous vertical position arc welding process developed in 1961, in which an arc is struck between a consumable electrode and the workpiece. ...

Power supplies

To supply the electrical energy necessary for arc welding processes, a number of different power supplies can be used. The most common classification is constant current power supplies and constant voltage power supplies. In arc welding, the voltage is directly related to the length of the arc, and the current is related to the amount of heat input. Constant current power supplies are most often used for manual welding processes such as gas tungsten arc welding and shielded metal arc welding, because they maintain a relatively constant current even as the voltage varies. This is important because in manual welding, it can be difficult to hold the electrode perfectly steady, and as a result, the arc length and thus voltage tend to fluctuate. Constant voltage power supplies hold the voltage constant and vary the current, and as a result, are most often used for automated welding processes such as gas metal arc welding, flux cored arc welding, and submerged arc welding. In these processes, arc length is kept constant, since any fluctuation in the distance between the wire and the base material is quickly rectified by a large change in current. For example, if the wire and the base material get too close, the current will rapidly increase, which in turn causes the heat to increase and the tip of the wire to melt, returning it to its original separation distance. Image File history File links Download high resolution version (2272x1704, 808 KB) // Overview This is a picture of the front of a Miller Syncrowave 350LX welding power source for Gas Tungsten Arc Welding and Shielded Metal Arc Welding. ... Image File history File links Download high resolution version (2272x1704, 808 KB) // Overview This is a picture of the front of a Miller Syncrowave 350LX welding power source for Gas Tungsten Arc Welding and Shielded Metal Arc Welding. ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ...

The direction of current used in arc welding also plays an important role in welding. Consumable electrode processes such as shielded metal arc welding and gas metal arc welding generally use direct current, but the electrode can be charged either positively or negatively. In welding, the positively charged anode will have a greater heat concentration and, as a result, changing the polarity of the electrode has an impact on weld properties. If the electrode is positively charged, it will melt more quickly, increasing weld penetration and welding speed. Alternatively, a negatively charged electrode results in more shallow welds. Non-consumable electrode processes, such as gas tungsten arc welding, can use either type of direct current, as well as alternating current. With direct current however, because the electrode only creates the arc and does not provide filler material, a positively charged electrode causes shallow welds, while a negatively charged electrode makes deeper welds. Alternating current rapidly moves between these two, resulting in medium-penetration welds. One disadvantage of AC, the fact that the arc must be re-ignited after every zero crossing, has been addressed with the invention of special power units that produce a square wave pattern instead of the normal sine wave, eliminating low-voltage time after the zero crossings and minimizing the effects of the problem. Diagram of a zinc anode in a galvanic cell. ... A square wave is a kind of basic waveform. ... In trigonometry, an ideal sine wave is a waveform whose graph is identical to the generalized sine function y = Asin[ω(x − α)] + C, where A is the amplitude, ω is the angular frequency (2π/P where P is the wavelength), α is the phase shift, and C...

Consumable electrode methods

One of the most common types of arc welding is shielded metal arc welding (SMAW), which is also known as manual metal arc welding (MMA) or stick welding. An electric current is used to strike an arc between the base material and a consumable electrode rod or 'stick'. The electrode rod is made of a material that is compatible with the base material being welded and is covered with a flux that protects the weld area from oxidation and contamination by producing CO₂ gas during the welding process. The electrode core itself acts as filler material, making a separate filler unnecessary. The process is very versatile, requiring little operator training and inexpensive equipment. However, weld times are rather slow, since the consumable electrodes must be frequently replaced and because slag, the residue from the flux, must be chipped away after welding. Furthermore, the process is generally limited to welding ferrous materials, though specialty electrodes have made possible the welding of cast iron, nickel, aluminium, copper and other metals. The versatility of the method makes it popular in a number of applications including repair work and construction. Image File history File links Download high resolution version (1000x714, 553 KB) Retrieved from [1] on March 20, 2005 by Spangineer. ... Image File history File links Download high resolution version (1000x714, 553 KB) Retrieved from [1] on March 20, 2005 by Spangineer. ... Shielded metal arc welding Shielded metal arc welding (SMAW), also known as manual metal arc (MMA) welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld. ... In metallurgy, flux is a substance which removes passivating oxides from the surface of a metal or alloy. ... The most fundamental reactions in chemistry are the redox processes. ... In order to meet Wikipedias quality standards, this article requires cleanup. ... Cast iron usually refers to grey cast iron, but can mean any of a group of iron-based alloys containing more than 2% carbon (alloys with less carbon are carbon steel by definition). ... For other uses, see Nickel (disambiguation). ... General Name, symbol, number aluminium, Al, 13 Chemical series poor metals Group, period, block 13, 3, p Appearance silvery Standard atomic weight 26. ... For other uses, see Copper (disambiguation). ...

Gas metal arc welding (GMAW) is a semi-automatic or automatic welding process that uses a continuous wire feed as an electrode and an inert or semi-inert shielding gas to protect the weld from contamination. When using an inert gas as shield it is known as Metal Inert Gas (MIG) welding. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems as well as alternating current can be used. GMAW welding speeds are relatively high due to the automatically fed continuous electrode, but is less versatile because it requires more equipment than the simpler SMAW process. Originally developed for welding aluminium and other non-ferrous materials in the 1940s, GMAW was soon applied to steels because it allowed for lower welding time compared to other welding processes. Today, GMAW is commonly used in industries such as the automobile industry, where it is preferred for its versatility and speed. However, because it employs a shielding gas, it is rarely used outdoors or in areas of air volatility. Gas metal arc welding Gas metal arc welding (GMAW), sometimes referred to by its subtypes, metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through... Shielding gases are inert or semi-inert gases that are commonly used in several welding processes, most notably gas metal arc welding and gas tungsten arc welding. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ... In electricity, current refers to electric current, which is the flow of electric charge. ... City lights viewed in a motion blurred exposure. ... General Name, symbol, number aluminium, Al, 13 Chemical series poor metals Group, period, block 13, 3, p Appearance silvery Standard atomic weight 26. ... The steel cable of a colliery winding tower. ... Automakers are companies that produce automobiles. ...

A related process, flux-cored arc welding (FCAW), uses similar equipment but uses wire consisting of a steel electrode tube surrounding a powder fill material. This cored wire is more expensive than the standard solid wire and generates extra shielding gas and/or slag, but it permits higher welding speed and greater metal penetration. A wire feeder configured for . ...

Submerged arc welding (SAW) is a high-productivity automatic welding method in which the arc is struck beneath a covering layer of flux. This increases arc quality, since contaminants in the atmosphere are blocked by the flux. The slag that forms on the weld generally comes off by itself and, combined with the use of a continuous wire feed, the weld deposition rate is high. Working conditions are much improved over other arc welding processes since the flux hides the arc and no smoke is produced. The process is commonly used in industry, especially for large products. As the arc is not visible, it requires full automatization. In-position welding is not possible with SAW. A submerged arc welder used for training. ...

Non-consumable electrode methods

Gas tungsten arc welding (GTAW), or tungsten inert gas (TIG) welding, is a manual welding process that uses a non-consumable electrode made of tungsten, an inert or semi-inert gas mixture, and a separate filler material. Especially useful for welding thin materials, this method is characterized by a stable arc and high quality welds, but it requires significant operator skill and can only be accomplished at relatively low speeds. It can be used on nearly all weldable metals, though it is most often applied to stainless steel and light metals. It is often used when quality welds are extremely important, such as in bicycle, aircraft and naval applications. A related process, plasma arc welding, also uses a tungsten electrode but uses plasma gas to make the arc. The arc is more concentrated than the GTAW arc, making transverse control more critical and thus generally restricting the technique to a mechanized process. Because of its stable current, the method can be used on a wider range of material thicknesses than can the GTAW process and is much faster. It can be applied to all of the same materials as GTAW except magnesium; automated welding of stainless steel is one important application of the process. A variation of the process is plasma cutting, an efficient steel cutting processs. Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. ... General Name, Symbol, Number tungsten, W, 74 Chemical series transition metals Group, Period, Block 6, 6, d Appearance grayish white, lustrous Standard atomic weight 183. ... The 630 foot high, stainless-clad (type 304L) Gateway Arch defines St. ... For other uses, see Bicycle (disambiguation). ... Plasma arc welding (PAW) is an extension of the gas tungsten arc welding (GTAW) process. ... For other uses, see Plasma. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Plasma cutting is a process used to cut steel and other metals (or sometimes other materials) using a plasma torch. ...

Other arc welding processes include atomic hydrogen welding, carbon arc welding, electroslag welding, electrogas welding, and stud arc welding. Atomic Hydrogen Welding (AHW) is an arc welding process that uses an arc between two metal tungsten electrodes in a shielding atmosphere of hydrogen and without the application of pressure. ... Carbon Arc Welding (CAW) is a process in which an arc is established between a nonconsumable carbon (graphite) electrode and the work, or between two carbon electrodes. ... Electroslag welding is a highly productive welding process developed in the United States during the 1930s. ... Electrogas welding (EGW) is a continuous vertical position arc welding process developed in 1961, in which an arc is struck between a consumable electrode and the workpiece. ... Stud welding is a form of spot welding where a bolt or specially formed nut is welded on to another metal part. ...

Corrosion issues

Some materials, notably high-strength steels, aluminium, and titanium alloys, are susceptible to hydrogen embrittlement. If the electrodes used for welding contain traces of moisture, the water decomposes in the heat of the arc and the liberated hydrogen enters the lattice of the material, causing its brittleness. Electrodes for such materials, with special low-hydrogen coating, are delivered in sealed moisture-proof packagings. New electrodes can be used straight from the can, but when moisture absorption may be suspected, they have to be dried by baking (usually at 800-1000 °F) in a drying oven. Flux used has to be kept very dry as well. [1] Hydrogen embrittlement is the process by which various metals, most importantly high-strength steel, become brittle and crack following exposure to hydrogen. ... In metallurgy, flux is a substance which removes passivating oxides from the surface of a metal or alloy. ...

Some austenitic stainless steels and nickel-based alloys are prone to intergranular corrosion. When subjected to temperatures around 700 °C for too long time, chromium reacts with carbon in the material, forming chromium carbide and depleting the crystal edges of chromium, impairing their corrosion resistance in a process called sensitization. Such sensitized steel undergoes corrosion in the areas near the welds where the temperature-time was favorable for forming the carbide. This kind of corrosion is often termed weld decay. Iron-carbon phase diagram, showing the conditions under which austenite (Î³) is stable in carbon steel. ... The 630 foot high, stainless-clad (type 304L) Gateway Arch defines St. ... For other uses, see Nickel (disambiguation). ... For specification language, see Alloy Analyzer. ... Intergranular corrosion (IGC), also termed intergranular attack (IGA), is a form of corrosion where the boundaries of crystallites of the material are more susceptible to corrosion than their insides. ... General Name, symbol, number chromium, Cr, 24 Chemical series transition metals Group, period, block 6, 4, d Appearance silvery metallic Standard atomic weight 51. ... General Name, symbol, number carbon, C, 6 Chemical series nonmetals Group, period, block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... Chromium carbide (Cr3C2) is an extremely hard refractory ceramic material. ...

Knifeline attack (KLA) is another kind of corrosion affecting welds, impacting steels stabilized by niobium. Niobium and niobium carbide dissolves in steel at very high temperatures. At some cooling regimes, niobium carbide does not precipitate, and the steel then behaves like unstabilized steel, forming chromium carbide instead. This affects only a thin zone several millimeters wide in the very vicinity of the weld, making it difficult to spot and increasing the corrosion speed. Structures made of such steels have to be heated in a whole to about 1950 °F, when the chromium carbide dissolves and niobium carbide forms. The cooling rate after this treatment is not important. [2] Intergranular corrosion (IGC), also termed intergranular attack (IGA), is a form of corrosion where the boundaries of crystallites of the material are more susceptible to corrosion than their insides. ... General Name, Symbol, Number niobium, Nb, 41 Chemical series transition metals Group, Period, Block 5, 5, d Appearance gray metallic Standard atomic weight 92. ... Niobium carbide (NbC and Nb2C) is an extremely hard refractory ceramic material, commercially used in tool bits for cutting tools. ...

Filler metal (electrode material) improperly chosen for the environmental conditions the finished parts will be subjected to can make them corrosion-sensitive as well. There are also issues of galvanic corrosion if the electrode composition is sufficiently dissimilar to the materials welded, or the materials are dissimilar themselves. Even between different grades of nickel-based stainless steels, corrosion of welded joints can be severe, despite that they rarely undergo galvanic corrosion when mechanically joined. [3] For the hazard, see corrosive. ... The Galvanic cell, named after Luigi Galvani, consists of two metals connected by an electrolyte which forms a salt bridge between the metals. ...

Safety issues

Welding can be a dangerous and unhealthy practice without the proper precautions; however, with the use of new technology and proper protection the risks of injury or death associated with welding can be greatly reduced. Because many common welding procedures involve an open electric arc or flame, the risk of burns is significant. To prevent them, welders wear protective clothing in the form of heavy leather gloves and protective long sleeve jackets to avoid exposure to extreme heat, flames, and sparks. Additionally, the brightness of the weld area leads to a condition called arc eye in which ultraviolet light causes the inflammation of the cornea and can burn the retinas of the eyes. Goggles and helmets with dark face plates are worn to prevent this exposure and, in recent years, new helmet models have been produced featuring a face plate that self-darkens upon exposure to high amounts of UV light. To protect bystanders, transparent welding curtains often surround the welding area. These curtains, made of a polyvinyl chloride plastic film, shield nearby workers from exposure to the UV light from the electric arc, but should not be used to replace the filter glass used in helmets. A welder is a tradesman who specialises in welding materials together. ... Protective clothing is clothing designed to protect either the wearers body or other items of clothing from hazards such as heat, chemicals and infection. ... Modern leather-working tools Leather is a material created through the tanning of hides and skins of animals, primarily cattlehide. ... // Leather gloves A glove (Middle English from Old English glof) is a type of garment which covers the hand of a human. ... Arc eye, also known as arc flash, welders flash, corneal flash burns, or flash burns, is a painful ocular condition sometimes experienced by welders who have failed to use adequate eye protection. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eyes optical power [1]. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus. ... Human eye cross-sectional view. ... Watersport goggles Blowtorching goggles and safety helmet Goggles and safety glasses are forms of protective eyewear that usually enclose or protect the eye area in order to prevent particulates or chemicals from striking the eyes. ... Welding helmets are typically worn when arc welding. ... Polyvinyl chloride Polyvinyl chloride, (IUPAC Polychloroethene) commonly abbreviated PVC, is a widely used thermoplastic polymer. ...

Welders are also often exposed to dangerous gases and particulate matter. Processes like flux-cored arc welding and shielded metal arc welding produce smoke containing particles of various types of oxides. The size of the particles in question tends to influence the toxicity of the fumes, with smaller particles presenting a greater danger. Additionally, many processes produce various gases (most commonly carbon dioxide and ozone, but others as well) that can prove dangerous if ventilation is inadequate. Furthermore, the use of compressed gases and flames in many welding processes pose an explosion and fire risk; some common precautions include limiting the amount of oxygen in the air and keeping combustible materials away from the workplace. Particulates, alternatively referred to as particulate matter (PM), aerosols or fine particles, are tiny particles of solid or liquid suspended in a gas. ... This article does not cite any references or sources. ... An oxide is a chemical compound containing an oxygen atom and other elements. ... Toxic redirects here, but this is also the name of a song by Britney Spears; see Toxic (song) Look up toxic and toxicity in Wiktionary, the free dictionary. ... It has been suggested that Ozone generator be merged into this article or section. ...

References

ASM International, formerly known as the American Society for Metals, is a professional organization for materials scientists and engineers working with metals. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Official language(s) None Capital Columbus Largest city Columbus Largest metro area Cleveland Area Ranked 34th - Total 44,825 sq mi (116,096 kmÂ²) - Width 220 miles (355 km) - Length 220 miles (355 km) - % water 8. ... Also see: 2002 (number). ... Geography Status City (1951) Region East of England Admin. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Official language(s) English de facto Capital Trenton Largest city Newark Area Ranked 47th - Total 8,729 sq mi (22,608 kmÂ²) - Width 70 miles (110 km) - Length 150 miles (240 km) - % water 14. ... This article is about the year. ... New York, New York and NYC redirect here. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... poop ... Year 1994 (MCMXCIV) was a common year starting on Saturday (link will display full 1994 Gregorian calendar). ... Wikipedia does not yet have an article with this exact name. ...

External links

Categories: Welding | Construction | Robotics Image File history File links This is a lossless scalable vector image. ... Turned chess pieces Metalworking is the craft and practice of working with metals to create structures or machine parts. ... Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. ... Shielded metal arc welding Shielded metal arc welding (SMAW), also known as manual metal arc (MMA) welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld. ... Gas metal arc welding Gas metal arc welding (GMAW), sometimes referred to by its subtypes, metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through... A wire feeder configured for . ... A submerged arc welder used for training. ... Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. ... Plasma arc welding (PAW) is an extension of the gas tungsten arc welding (GTAW) process. ... This is a list of welding processes, separated into their respective categories. ... â€œOxyacetyleneâ€ redirects here. ... Resistance welding refers to a group of welding processes that produce coalescence of the faying surfaces with the heat obtained from resistance of the workpieces to the flow of the welding current in a circuit of which the workpieces are part, and by the application of pressure. ... A miller spot welder Spot welding is a type of resistance welding used to weld various sheet metals. ... Forge welding is a welding process of heating two or more pieces of wrought iron or steel until their surfaces are malleable and then hammering them together. ... Ultrasonic welding is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are used to weld objects together, usually plastics, and especially for joining dissimilar materials. ... Electron beam welding is a welding process where the energy to melt the material is applied by an electron beam. ... Laser beam welding is a technique in manufacturing whereby two or more pieces of material (usually metal) are joined by together through use of a laser beam. ... A high output constant current welding power supply for use with GTAW and SMAW A welding power supply is an electrical device that provides an electrical current to perform welding procedures which require electricity. ... An electrode is an electrical conductor used to make contact with a metallic part of a circuit (e. ... A filler metal is a metal added in the making of a joint through welding, brazing, or soldering. ... Shielding gases are inert or semi-inert gases that are commonly used in several welding processes, most notably gas metal arc welding and gas tungsten arc welding. ... Spot welding: KUKA industrial robots welding a car body in the white section of a production line. ... Welding helmets are typically worn when arc welding. ... The cross-section of a welded butt joint, with the darkest gray representing the weld or fusion zone, the medium gray the heat affected zone, and the lightest gray the base material. ... Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. ... Residual stresses are stresses that remain after the original cause of the stresses (external forces, heat gradient) has been removed. ... Arc eye, also known as arc flash, welders flash, corneal flash burns, or flash burns, is a painful ocular condition sometimes experienced by welders who have failed to use adequate eye protection. ... Underwater welding Underwater welding refers to a number of distinct welding processes that are performed underwater. ... Brazing is a joining process whereby a non-ferrous filler metal or alloy is heated to melting temperature above 450Â°C (842Â°F), or, by the traditional definition that has been used in the United States, above 800Â°F (425)Â°C and distributed between two or more close-fitting parts... (De)soldering a contact from a wire. ... Turned chess pieces Metalworking is the craft and practice of working with metals to create structures or machine parts. ... A typical steel fabrication shop Fabrication, when used chas an industrial term, applies to the building of machines and structures by cutting, shaping and assembling components made from raw materials. ... Casting may be used to create artistic sculptures Casting is a manufacturing process by which a molten material such as metal or plastic is introduced into a mold, allowed to solidify within the mold, and then ejected or broken out to make a fabricated part. ... A lathe is a common tool used in machining. ... Georg Agricola, author of De re metallica, an important early book on metal extraction Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. ... Jewelry (the American spelling; spelled jewellery in Commonwealth English) consists of ornamental devices worn by persons, typically made with gems and precious metals. ...

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