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http://dx.doi.org/10.7842/kigas.2013.17.5.64

Non-Destructive Testing of Damaged Thermoplastic Pipes Electrofusion Joints Using Phased Array Ultrasonic  

Kil, Seong-Hee (Dept. of Gas Safety R&D Institute, Korea Gas Safety Corporation)
Kim, Byung-Duk (Dept. of Gas Safety R&D Institute, Korea Gas Safety Corporation)
Kwon, Jeong-Rock (Dept. of Gas Safety R&D Institute, Korea Gas Safety Corporation)
Yoon, Kee-Bong (Dept. of Mechanical Engineering of Chung-Ang University)
Publication Information
Journal of the Korean Institute of Gas / v.17, no.5, 2013 , pp. 64-68 More about this Journal
Abstract
Non destructive testing(NDT) methods of electrofusion(EF) joints of thermoplastics pipes are required for fusion joint safety and for the long term reliability of a pipe system. Electrofusion joints, which are joined at the proper fusion process and procedures, may encounter defects due to the difference of ovality between pipes and coupling, improper fusion process or porosity result from electrofusion joining. These defects can cause the failure of pipeline and by extension, they can be caused the limit to expand the use of plastics pipes. This paper studies inspection results using ultrasonic imaging method for damaged polyethylene electrofusion joints. Gas was leaking from 250mm diameter polyethylene electrofusion joints at February 2004 which was electrofused at December 1994 and operation pressure was 2.45kPa. First, surface inspection was conducted and then in order to find the types of defects examination using ultrasonic imaging method was performed. Lack of fusion and inappropriate inserting for polyethylene pipes into electrofusion coupling were found and causes of the gas leak were judged that misalignment and insert defect. Cutting inspection was performed and each inspection results were compared to. Results of ultrasonic imaging method and cutting inspection were the same.
Keywords
Thermoplastics pipes; Electrofusion; NDT; Phased array ultrasonic;
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  • Reference
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