Non destructive testing of materials subject to ...（非破坏性测试材料的话题）.pdf

17th World Conference on Nondestructive Testing, 25-28 Oct 2008, Shanghai, China Non Destructive Testing Of Materials Subject To Atmospheric Stress Corrosion Cracking Martin VAN DALEN ¹, Craig WICKER ², Graham .J. WILSON ² ¹ Southern African Institute of Welding, Johannesburg, South Africa Phone: +27 11 836 4121, Fax: +27 11 836 4132, E-mail: vandalenm@saiw.co.za Web: http:/www.saiw.co.za ² Eskom, Cape town, South Africa E-mail: Craig.Wicker@eskom.co.za, GrahamJ.Wilson@eskom.co.za Abstract In-service inspection revealed atmospheric stress corrosion cracking (ASCC), on 304L stainless steel piping. The method requiring inspection qualification was a surface method, namely Penetrant Testing as physical dimensions of the smallest flaw requiring detection by PT was ill defined for both pitting and cracking defects. Qualification was considered in terms of flaw volume together with absolute flaw linear dimensions. Inspection qualification would therefore determine the adequacy of the applied technique by both physical reasoning and by empirical measurement to determine the largest flaw that could escape detection. Keywords: Atmospheric Stress Corrosion Cracking, Detection by Liquid Penetrant Inspection Introduction During the life of any industrial plant it may be necessary to perform routine In-service inspection on critical systems. In-service inspection in the context of this paper is considered to be “Examinations and tests conducted periodically to demonstrate structural integrity and/or operability of components important to safety”. In one such example, In-service inspection revealed atmospheric stress corrosion cra