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外文资料翻译HISTORY OF UNDERWATER WELDING TECHNOLOGYUnderwater welding technology is the development of the marine, offshore oil exploitation as well as assembly, maintenance such as oil platforms, pipelines and submarine positions in large marine structures such as one of the key technologies, but also ships emergency repair, salvage, construction of bridges and other necessary technically work means. Nuclear power development is the trend of the world in nuclear power plants within the reactor pressure vessel (RPV) for long-term work in the water, susceptible to stress corrosion cracking of the damage, structural repair of nuclear power, will face many challenges. Tooften use radiation-related underwater welding method, in order to reduce the working staff. Classification of underwater welding underwater welding generally divided into three categories: wet, dry, and local dry. And the dry can be divided into high-pressure dry underwater welding and common-pressure underwater welding pressure. Local laws, including drainage cover dry type, high-pressure curtain-style, steel brush, mobile air box and plasma arc MIG local dry method. Welding method used generally coated electrode welding, GTAW, GMWA, and FCAW. In addition to welding underwater welding in addition there is an explosion welding and FSW (friction stitch welding friction stitch welding), these two methods are all connected by solid phase technology. Following the development of underwater welding course: 1 Underwater wet welding technology In 1802, a scholar named Humphrey pointed out that a continuous arc can burn under water, that pointed out the possibility of underwater welding, but its practical application is more than 100 years later, can not move the structure on land welding was done under the circumstances. In 1917, the British naval dockyard welders using underwater welding methods to block in the underwater part of ship rivets leaking cracks, this is the first application of underwater welding. Th