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Plagiarism will be detected by Copyscape. This is a featured article. Click here for more information. The electrode holder holds the electrode as it slowly melts away. The molten weld and the arc zone are protected from atmospheric contamination by being “submerged” under the flux blanket. In general, an efficient method, but limited to relatively thin material. Welding technology advanced quickly during the early 20th century as the world wars drove the demand for reliable and inexpensive joining methods.
Following the wars, several modern welding techniques were developed, including manual methods like SMAW, now one of the most popular welding methods, as well as semi-automatic and automatic processes such as GMAW, SAW, FCAW and ESW. Today, the science continues to advance. The history of joining metals goes back several millennia. 5th century BC that Glaucus of Chios “was the man who single-handedly invented iron welding”. India about 310 AD and weighing 5. 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.
In 1808, Davy, who was unaware of Petrov’s work, rediscovered the continuous electric arc. In 1905, Russian scientist Vladimir Mitkevich proposed using a three-phase electric arc for welding. Holslag but did not become popular for another decade. 1885, who produced further advances over the next 15 years.
1893, and around that time another process, oxyfuel welding, became well established. 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. 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. World War I caused a major surge in the use of welding processes, with the various military powers attempting to determine which of the several new welding processes would be best.
The British primarily used arc welding, even constructing a ship, the “Fullagar” with an entirely welded hull. Arc welding was first applied to aircraft during the war as well, as some German airplane fuselages were constructed using the process. During the 1920s, major advances were made in welding technology, including the introduction of automatic welding in 1920, in which electrode wire was fed continuously. 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. During the middle of the century, many new welding methods were invented. Submerged arc welding was invented the same year and continues to be popular today. 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 1953, the Soviet scientist N. 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. All of these four new processes continue to be quite expensive due the high cost of the necessary equipment, and this has limited their applications. File:Man welding a metal structure in a newly constructed house in Bengaluru, India. To supply the electrical power necessary for arc welding processes, a variety of different power supplies can be used.
In arc welding, the length of the arc is directly related to the voltage, and the amount of heat input is related to the current. 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. The type of current used plays an important role in arc 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. If the electrode is positively charged, the base metal will be hotter, increasing weld penetration and welding speed. Alternatively, a negatively charged electrode results in more shallow welds. Nonconsumable electrode processes, such as gas tungsten arc welding, can use either type of direct current, as well as alternating current. However, with direct current, 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. The electrode core itself acts as filler material, making a separate filler unnecessary.