| Abstract from DBPedia | Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as brazing and soldering, which do not melt the base metal (parent metal). In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that, based on weld configuration (butt, full penetration, fillet, etc.), can be stronger than the base material. Pressure may also be used in conjunction with heat or by itself to produce a weld. Welding also requires a form of shield to protect the filler metals or melted metals from being contaminated or oxidized. Many different energy sources can be used for welding, including a gas flame (chemical), an electric arc (electrical), a laser, an electron beam, friction, and ultrasound. While often an industrial process, welding may be performed in many different environments, including in open air, under water, and in outer space. Welding is a hazardous undertaking and precautions are required to avoid burns, electric shock, vision damage, inhalation of poisonous gases and fumes, and exposure to intense ultraviolet radiation. Until the end of the 19th century, the only welding process was forge welding, which blacksmiths had used for millennia to join iron and steel by heating and hammering. Arc welding and oxy-fuel welding were among the first processes to develop late in the century, and electric resistance welding followed soon after. Welding technology advanced quickly during the early 20th century as world wars drove the demand for reliable and inexpensive joining methods. Following the wars, several modern welding techniques were developed, including manual methods like shielded metal arc welding, now one of the most popular welding methods, as well as semi-automatic and automatic processes such as gas metal arc welding, submerged arc welding, flux-cored arc welding and electroslag welding. Developments continued with the invention of laser beam welding, electron beam welding, magnetic pulse welding, and friction stir welding in the latter half of the century. Today, as the science continues to advance, robot welding is commonplace in industrial settings, and researchers continue to develop new welding methods and gain greater understanding of weld quality.溶接（ようせつ、英語：welding）とは、2個以上の部材の接合部に、熱又は圧力もしくはその両者を加え、必要があれば適当な溶加材を加えて、接合部が連続性を持つ一体化された1つの部材とする接合方法。更に細かく分類すると、融接、圧接、ろう付けに分けられる。現在に至るまで一般的な溶接という表記のほかにかつては鎔接や熔接の文字も並んで利用されていたが、「鎔」「熔」ともに当用漢字に入らず、今日では主に「溶」の文字が用いられている。 溶接は青銅器時代（ろう付、メソポタミアのレリーフ）からも見出され、日本では弥生時代の銅鐸にも溶接の跡が発見されている。現代では、建設業、自動車産業、宇宙工学（航空宇宙産業）、造船などの先端技術だけでなく生活をささえる基本的な古くて新しい技術である。 (Source: http://dbpedia.org/resource/Welding) |
