The results of the study of the mechanism of origin and growth of corrosion cracks under stress on the pipes of the gas lines is presented in the article. It was found that the elements of corrosion cracking, which are most susceptible to defect formation and have a high level of internal stresses, are related to weld-affected zones of the trunk gas lines welded joints. Laboratory study was conducted concerning the fragments of the welded joints of weld-affected zones of the trunk gas lines, which are tentatively loaded with an internal pressure of 60, 75, 94 and 130 kgf/cm2. The nature of metal destruction is described, and the assessment was made of the state of the crack-like defects in the pipeline metal using optical and magnetic measurements.
Based on the results of visual inspection of fracture boundaries of the trunk line weld-affected zone, it was identified that the defects are representing interaction and merge, which dimensions under the relevant pressure could become critical, and the cracks themselves could form the source of destruction. In the laboratory studies the internal critical load on the pipe wall (experimental fragment) was simulated at which the growth and merge of the corrosion cracks take place. The study made allowed to identify the level of critical load at which happens the destruction of the elements of the welded joint. The results of the study will allow to increase the reliability of diagnostic examination of the process of defect formation and to predict the behavior of the crack-like defects in the pipe metal. This will result in significant reduction of the probability of the trunk lines accidents, and, therefore, to increase safety of gas transfer. The methods of the laboratory research described in this article, as well as its results can be used when defining the causes of the trunk lines destruction, which will allow to significantly reduce their accident rate in future.
- Safety regulations for hazardous production facilities of the trunk lines: Federal rules and regulations in the field of industrial safety. Ser. 08. Iss. 20. Moscow: ZAO NTTs PB, 2014. 40 p. (In Russ.).
- On industrial safety of hazardous production facilities: Federal Law of July 21, 1997 № 116-FZ. Available at: http://www.mchs.gov.ru/law/Federalnie_zakoni/item/5378600 (accessed: January 17, 2019). (In Russ.).
- Aubakirova F.Kh., Bukleshev D.O., Velkin V.I., Vorzhev V.B., Denisov K.S., Drabenko V.A., Drabenko V.A., Drabenko D.V., Ershov V.V., Rudenko N.V. Energy efficiency as an indicator of the scientific-technical and economic potential of the society. Available at: http://scipro.ru/conf/monographenergetics.pdf (accessed: January 24, 2019). (In Russ.).
- Varlamov D.P., Kanaykin V.A., Matvienko A.F., Steklov O.I. Defectiveness monitoring and forecast of the gas trunk lines state in Russia. Ekaterinburg: Uralskiy tsentr akademicheskogo obsluzhivaniya, 2012. 250 p. (In Russ.).
- Peterfalvi F. Modernizing the leak-detection system for mol’s oil-products pipelines — Part 1. Pipeline Science and Technology. 2017. Vol. 1. № 2. pp. 153–160.
- Surkov Yu.P., Khoroshikh A.V., Rybalko V.G. Study of cases of corrosion cracking of the operating gas pipelines. Korrozionnoe rastreskivanie trubnykh staley: ceminar po problemam korrozionnogo rastreskivaniya (Corrosion cracking of pipe steels: seminar on the problems of corrosion cracking). Ukhta, 1996. pp. 57–62. (In Russ.).
- Dolgov I.A., Gorchakov V.A., Pakhtusov S.V., Knoshinskiy Z., Surkov Yu.P., Rybalko V.G. Assessment of stress corrosion cracking cracks behavior when the pipe is loaded with internal pressure. Defektoskopiya = Defectoscopy. 2002. № 2. pp. 83–89. (In Russ.).
- Surkov Yu.P., Rybalko V.G., Pavlov M.Yu., Sycheva T.S. Development of corrosion cracking cracks in the gas pipelines. Fizika metallov i metallovedenie = Physics of Metal and Metallography. 1995. № 80. Iss. 5. pp. 141–147. (In Russ.).
- Chettouh S., Hamzi R. Algerian Oil Refining Industry: Analysis of Past Industrial Accidents of the Period 2002–2013. World Applied Sciences Journal. 2014. Vol. 29. № 7. pp. 933–939.
- Bukleshev D.O. The effect of presence and the magnitude of stresses in the weld-affected zone of the welded joints on the strength characteristics and the pipelines service life. Territoriya Neftegaz. Korroziya = Territory of Neftegaz. Corrosion. 2016. № 2 (34). pp. 30–35. (In Russ.).
- Romanenko S.V. Analysis of the causes of destruction of gas trunk line in the transverse direction. Gazovaya promyshlennost = Gas industry. 2008. № 1. pp. 55–57. (In Russ.).
- Vladimirova A.I., Kershenbauma V.Ya. Industrial safety and reliability of the trunk pipelines. Moscow: Natsionalnyy institut nefti i gaza, 2009. 696 p. (In Russ.).