In-Service Degradation of Mechanical Characteristics of Pipe Steels in Gas Mains

  • H. V. Krechkovs’ka
  • O. T. Tsyrul’nyk
  • O. Z. StudentEmail author

The laws governing change in mechanical characteristics under tension in air of steels of different strength levels in the initial state and after long-term exploitation on gas mains have been established. Because of in-service degradation, ductility characteristics decrease, and strength characteristics increase. The higher the strength level of steel in the initial state, the weaker the effect of change in its characteristics. In spite of the longest-term exploitation, the ductility characteristics of Kh70 steel did not practically change, whereas those of 17G1S and Kh60 steels decreased greatly after less long-term exploitation. These effects are caused by the structural peculiarities of steels. Indeed, a texture was detected both in the axial and in the diametral section of pipes made of these steels. The length of almost continuous rows of pearlite grains in the axial direction reached 500 μm and in the transverse direction 40 μm. The increased etching of interfaces between ferrite and pearlite grains both along and across the pipe rolling direction was attributed to damages along these interfaces. Such damages were traps for hydrogen and hindered its diffusion redistribution in the cross-section of pipes. Hydrogen accumulated in them promoted lamination along interfaces and facilitated strain localization in the most weakened sections. Signs of the in-service degradation of steels of different strength levels have been detected fractographically. Firstly, it is the textured nature of specimen fractures at the macrolevel as laminations in the pipe rolling direction, which are caused by in-service damages of steels. We believe that hydrogen absorbed by the metal during long-term exploitation and accumulated in defects along interfaces gave rise to them. Secondly, in the central part of mode I fractures, large and flat lens-shaped areas with small dimples, which accumulate hydrogen at the bottom, which facilitated the destruction of partitions between them, were detected. Thirdly, within the boundaries of the conical parts of the fractures of all steels under investigation, amid shear mode small parabolic dimples, large flat dimples with the characteristic relief of the parallel traces of the rise of slip bands to their surface are observed. We suppose that this proves their existence in the section of specimens as early as before tensile test. The above structural and fractographic features of degradation are inherent in all steels, particularly in 17G1S steel, whose hardening was accompanied by a greater decrease in ductility due to degradation.


gas pipelines in-service degradation mechanical characteristics fractodiagnostics 


  1. 1.
    H. V. Krechkovs’ka, A. B. Mytsyk, O. Z. Student, and H. M. Nykyforchyn, “Diagnostic indications of the inservice degradation of the pressure regulator of a gas-transportation system,” Mater. Sci., 52, No. 2, 233–239 (2016).CrossRefGoogle Scholar
  2. 2.
    P. Marushchak, H. Danylyshyn, I. Okipnyi, and A. Sorochak, “Fractodiagnostics of multiple in-service and technological crack-like defects,” Mashynoznavstvo, Nos. 3–4, 40–44 (2011).Google Scholar
  3. 3.
    K. O. Findley, M. K. O’Brien, and H. Nako, “Critical Assessment 17: Mechanisms of hydrogen induced cracking in pipeline steels,” Mater. Sci. Technol., 31, No. 14, 1673–1680 (2015).CrossRefGoogle Scholar
  4. 4.
    P. Maruschak, S. Panin, M. Chausov, et al., “Effect of long-term operation on steels of main gas pipeline: Structural and mechanical degradation,” J. King Saud Univ. - Eng. Sci., 30, No. 4, 363–367 (2018).Google Scholar
  5. 5.
    A. Ya. Krasovskii and I. V. Orynyak, “Strength and reliability of piping systems,” Strength Mater., 42, No. 5, 613–621 (2010).CrossRefGoogle Scholar
  6. 6.
    N. Taylor, H. M. Nykyforchyn, O. T. Tsyrulnyk, and O. Z. Student, “Effect of hydrogenation on the fracture mode of a reactor pressure-vessel steel,” Mater. Sci., 45, No. 5, 613–625 (2009).CrossRefGoogle Scholar
  7. 7.
    H. V. Krechkovs’ka, “Fractographic signs of the mechanisms of transportation of hydrogen in structural steels,” Mater. Sci., 51, No. 4, 509–513 (2016).CrossRefGoogle Scholar
  8. 8.
    P. O. Maruschak, S. V. Panin, M. G. Chausov, et al., “Effect of long-term operation on steels of main gas pipeline. Reduction of static fracture toughness,” J. Nat. Gas Sci. Eng., 38, 182–186 (2017).CrossRefGoogle Scholar
  9. 9.
    M. A. Mohtadi-Bonab, J. A. Szpunar, R. Basu, and M. Eskandari, “The mechanism of failure by hydrogen induced cracking in an acidic environment for API 5L X70 pipeline steel,” Int. J. Hydrogen Energ., 40, No. 2, 1096–1107 (2015).CrossRefGoogle Scholar
  10. 10.
    H. V. Krechkovs’ka, S. R. Yanovs’kyi, O. Z. Student, and H. M. Nykyforchyn, “Fractographic signs of the inservice degradation of welded joints of oil mains,” Mater. Sci., 51, No. 2, 165–171 (2015).CrossRefGoogle Scholar
  11. 11.
    P. O. Marushchak, R. T. Bishchak, and D. Ya. Baran, Scattered and Localized Damage of Heat-Resistant Steels [in Ukrainian], Libra Terra, Ternopil (2016).Google Scholar
  12. 12.
    S. O. Kotrechko, A. Y. Krasowsky, Yu. Ya. Meshkov, V. M. Torop, “Effect of long-term service on the tensile properties and capability of pipeline steel 17GS to resist cleavage fracture,” Int. J. Pres. Ves. Pip., 81, No. 4, 337–344 (2004).CrossRefGoogle Scholar
  13. 13.
    R. Ya. Kosarevych, O. Z. Student, L. M. Svirs’ka, et al., “Computer analysis of characteristic elements of fractographic images,” Mater. Sci., 48, No. 4, 474–481 (2013).CrossRefGoogle Scholar
  14. 14.
    O. Z. Student, B. P. Rusyn, B. P. Kysil, et al., “Quantitative analysis of structural changes in steel caused by high-temperature holding in hydrogen,” Mater. Sci., 39, No. 1, 17–24 (2003).CrossRefGoogle Scholar
  15. 15.
    I. M. Zhuravel’, L. M. Svirs’ka, O. Z. Student, et al., “Automated determination of grain geometry in an exploited steam-pipeline steel,” Mater. Sci., 45, No. 3, 350–357 (2009).CrossRefGoogle Scholar
  16. 16.
    R. A. Vorobel’, I. M. Zhuravel’, L. M. Svirs’ka, and O. Z. Student, “Automatic selection and quantitative analysis of carbides on grain boundaries of 12Kh1MF steel after operation at a steam pipeline of a thermal power plant,” Mater. Sci., 47, No. 3, 393–400 (2011).CrossRefGoogle Scholar
  17. 17.
    Yu. S. Nechaev, “Physical complex aging, embrittlement and fracture problems of metallic materials in hydrogen power industry and of gas mains,” Usp. Fiz. Nauk, No. 178, 709–726 (2008).CrossRefGoogle Scholar
  18. 18.
    A. N. Kuzyukov et al., “Hydrogen degradation of materials and related phenomena,” in: Hydrogen Economy and Hydrogen Treatment of Materials [in Russian] (Proc. of the Vth Int. Conf., May 21–25, 2007, Donetsk), Vol. 2, DonIFTs IAU, Donetsk (2007).Google Scholar
  19. 19.
    G. A. Filippov and O. V. Livanova, Degradation Processes and Their Effect on the Crack Resistance of Pipe Steels after Long-Term Exploitation, Aging Problems of Steels of Main Pipelines [in Russian], Universitetskaya Kniga, Nizhni Novgorod (2006).Google Scholar
  20. 20.
    L. Tau and S. L. I. Chan, “Effects of ferrite/pearlite alignment on the hydrogen permeation in a AISI 4130 steel,” Mater. Lett., 29, Nos. 1–3, 143–147 (1996).Google Scholar
  21. 21.
    H.-L. Lee and S. L.-I. Chan, “Hydrogen embrittlement of AISI 4130 steel with an alternate ferrite/pearlite banded structure,” Mater. Sci. Eng. A, 142, No. 2, 193–201 (1991).Google Scholar
  22. 22.
    S. L. I. Chan and J. A. Charles, “Effect of carbon content on hydrogen occlusivity and embrittlement of ferrite-pearlite steels,” J. Mater. Sci. Technol., 2, No. 9, 956–962 (1986).CrossRefGoogle Scholar
  23. 23.
    K. Ichitani and M. Kanno, “Visualization of hydrogen diffusion in steels by high sensitivity hydrogen microprint technique,” Sci. Technol. Adv. Mat., 4, No. 6, 545– 551 (2003).CrossRefGoogle Scholar
  24. 24.
    M. M. Islam, C. Zou, A. C. T. van Duin, and S. Raman, “Interactions of hydrogen with the iron and iron carbide interfaces: a ReaxFF molecular dynamics study,” Phys. Chem. Chem. Phys., 18, No. 2, 761–771 (2016).CrossRefGoogle Scholar
  25. 25.
    H. Nykyforchyn, O. Zvirko, O. Tsyrulnyk, and N. Kret, “Analysis and mechanical properties characterization of operated gas main elbow with hydrogen assisted large-scale delamination,” Eng. Fail. Anal., 82, 364–377 (2017).CrossRefGoogle Scholar
  26. 26.
    O. I. Zvirko, A. B. Mytsyk, O. T. Tsyrulnyk, et al., “Corrosion degradation of steel of long-term operated gas pipeline elbow with large-scale delamination,” Mater. Sci., 52, No. 6, 861–865 (2017).CrossRefGoogle Scholar
  27. 27.
    H. M. Nykyforchyn, O. I. Zvirko, and O. T. Tsyrulnyk, “Hydrogen assisted macrodelamination in gas lateral pipe,” Proc. Struct. Integr., 2, 501–508 (2016).CrossRefGoogle Scholar
  28. 28.
    L. E. Kharchenko, O. E. Kunta, O. I. Zvirko, et al., “Diagnostics of hydrogen macrodelamination in the wall of a bent pipe in the system of gas mains,” Mater. Sci., 51, No. 4, 530–537 (2016).CrossRefGoogle Scholar
  29. 29.
    Y. Murakami, “Effect of hydrogen on fatigue crack growth of metals,” in: Proc. of the 17th Eur. Conf. on Fracture 2008: Multilevel Approach to Fracture of Materials, Components and Structures (September 2–5, 2008, Brno, Czech Republic), ESIS Czech Chapter (2008), pp. 25–42.Google Scholar

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Authors and Affiliations

  • H. V. Krechkovs’ka
    • 1
  • O. T. Tsyrul’nyk
    • 1
  • O. Z. Student
    • 1
    Email author
  1. 1.Karpenko Physico-Mechanical InstituteNational Academy of Sciences of UkraineLvivUkraine

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