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Sustained load cracking or SLC is a metallurgical phenomenon that occasionally develops in pressure vessels and structural components under stress for sustained periods of time.〔Hervé Barthélémy, David Birch. Wolfgang Dörner. Jörgen Erlandsson, Giorgio Gabrieli, Alexander Kriese, Els Vandererven, Andy Webb, (2004), Recommendations for avoidance of sustained load cracking of aluminium alloy cylinders, IGC Doc 57/11/E, Revision of IGC Doc 57/04/E European Industrial Gases Association AISBL, Brussels. http://www.eiga.org/index.php?id=181 accessed 1 Sept 2012〕 It is particularly noted in aluminium pressure vessels such as diving cylinders.〔http://www.luxfercylinders.com/frequently-asked-questions/sustained-load-cracking, accessed 30 Aug 2012〕〔Bill High, Cracking and Ruptures of SCBA and SCUBA Aluminum Cylinders Made from 6351 Alloy, PSI, Inc. http://www.hawaii.edu/ehso/diving/Cracking%20and%20Ruptures%20of%20SCBA%20and%20SCUBA%20Aluminum%20Cylinders.pdf accessed 30 August 2012〕 Sustained load cracking is not a manufacturing defect; it is a phenomenon associated with certain alloys and service conditions: *6351 aluminum alloy *Over stressing due to excessive filling pressure *Abuse and mechanical damage ==Occurrence== Crack growth is reported to be very slow by Luxfer, a major manufacturer of aluminium high pressure cylinders.〔 Cracks are reported to develop over periods in the order of eight or more years before reaching a stage where the cylinder is likely to leak, which allows timely detection by properly trained inspectors using eddy current crack detection equipment. SLC cracks have been detected in cylinders produced by several manufacturers, including Luxfer, Walter Kidde, and CIG gas cylinders. Most of the cracking has been observed in the neck and shoulder areas of cylinders though some cracks in the cylindrical part have also been reported.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sustained load cracking」の詳細全文を読む スポンサード リンク
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