Accidents due to stress corrosion cracking is one of the most serious problems of the gas transmission companies. Based on statistics, similar defects occur in places of the layer separation of the film type protective coating applied during gas pipelines construction. Associated factors for the occurrence of the under film corrosion: pipe poor surface preparation before protective coating application, presence of highly corrosive environment at the place of layer separation. It is impossible to detect such problems with the help of electrometric inspections, electrochemical protection as the main method of corrosion processes control is also ineffective.
There are several methods of quality control of protective coatings and the variety of instruments for its implementation. However, the approaches currently used have been developed without considering the features of continuous insulation of gas pipelines long sections, up-to-date insulation materials and technologies for their application, therefore, effective control is not always possible.
The authors of the article have created the concept of the quality control automated complex for the insulation works based on existing experience in the development, production and testing of portable flaw detectors. The project provides for the combination of eddy current control of the insulation coating thickness and acoustic impedance method. Upgraded acoustic impedance and eddy current sensors are integrated into quick-change cartridges of the measuring unit. In addition, it is possible to install eddy current repair diagnostics sensors for searching defects of general corrosion and stress corrosion cracking.
S.V. Rybalko, General Director, Rybalko@neftegazdiagnostika.ru OOO «NPP «Neftegazdiagnostika», Ekaterinburg, Russia V.G. Rybalko, Cand. Sci. (Eng.), Senior Researcher T.A. Efremov, Lead Engineer IFM UrO RAN, Ekaterinburg Russia A.V. Kolpashchikova, Graduate Student INMT FGAOU VO «UrFU named after the first President of Russia B.N. Yeltsin»
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