Steel and Composite Structures

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

A novel semi-empirical technique for improving API X70 pipeline steel fracture toughness test data

  • Received : 2021.05.16
  • Accepted : 2023.06.13
  • Published : 2024.05.25
⟨ Previous Next ⟩

Abstract

Accurate measurement of KIC values for gas pipeline steels is important for assessing pipe safety using failure assessment diagrams. As direct measurement of KIC was impossible for the API X70 pipeline steel, multi-specimen fracture tests were conducted to measure JIC using three-point bend geometry. The J values were calculated from load-displacement (F-δ) plots, and the associated crack extensions were measured from the fracture surface of test specimens. Valid data points were found for the constructed J-Δa plot resulting in JIC=356kN/m. More data points were added analytically to the J-Δa plot to increase the number of data points without performing additional experiments for different J-Δa zones where test data was unavailable. Consequently, displacement (δ) and crack-growth (Δa) from multi-specimen tests (with small displacements) were used simultaneously, resulting in the variation of Δa-δ (crack growth law) and δ-Δa obtained for this steel. For new Δa values, corresponding δ values were first calculated from δ-Δa. Then, corresponding J values for the obtained δ values were calculated from the area under the F-δ record of a full-fractured specimen (with large displacement). Given Δa and J values for new data points, the developed J-Δa plot with extra data points yielded a satisfactory estimation of JIC=345kN/m with only a -3.1% error. This is promising and showed that the developed technique could ease the estimation of JIC significantly and reduce the time and cost of expensive extra fracture toughness tests.

Keywords

Acknowledgement

The authors gratefully acknowledge the supply of API X70 gas pipe used in this study by Sadid Pipe and Equipment Company (Tehran, Iran), as well as the assistance of Dr. Ashrafi in 3PB testing and Dr. Khazaei in optical microscopy (at the University of Birjand).

References

  1. Akram, A., Mustaffa, Z. and Badri Albarody, T.M. (2020), "Burst capacity of pipe under corrosion defects and repaired with thermosetting liner", Steel Compos. Struct., 35(2), 171-186. https://doi.org/10.12989/scs.2020.35.2.171.
  2. API 579 (2000), Fitness for Service, API Recommended Practice 579, American Petroleum Institute; USA.
  3. API 5L (2008), Specifications for Line Pipe, American Petroleum Institute, Washington D.C, USA.
  4. ASTM E1820 (2002), Standard Test Method for Measurement of Fracture Toughness, American Society for Testing and Materials, USA.
  5. Bellahcene, T. and Aberkane, M. (2017), "Estimation of fracture toughness of cast steel container from Charpy impact test data", Steel Compos. Struct., 25(6), 639-648. https://doi.org/10.12989/scs.2017.25.6.639.
  6. BS 7448-4 (1997), Fracture Mechanics Toughness Tests - Part 4: Method for Determination of Fracture Resistance Curves and Initiation Values for Stable Crack Extension in Metallic Materials, British Standards Institution; UK.
  7. BS 7910 (1999), Guide and Methods for Assessing the Acceptability of Flaws in Metallic Structures, British Standards Institution; UK.
  8. Chen, X., Lu, H.B., Chen, G. and Wang, X. (2015), "A comparison between fracture toughness at different locations of longitudinal submerged arc welded and spiral submerged arc welded joints of API X80 pipeline steels", Eng. Fract. Mech., 148, 110-121. https://doi.org/10.1016/j.engfracmech.2015.09.003.
  9. Cotterell, B. (2002), "The past, present, and future of fracture mechanics", Eng. Fract. Mech., 69(5), 533-553. https://doi.org/10.1016/S0013-7944(01)00101-1.
  10. Fan, M., Yi, D.K. and Xiao, Z.M. (2014), "Elastic-plastic fracture behavior analysis on a Griffith crack in the cylindrical three-phase composites with generalized Irwin model", Int. J. Appl. Mech., 6(4), 1450045. https://doi.org/10.1142/S1758825114500458.
  11. Feng, L., Liu, T., Qian, X. and Chen, C. (2022), "A complete integrity assessment of welded connections under high and low cycle fatigue followed by fracture failure", Steel Compos. Struct., 43(4), 465-481. https://doi.org/10.12989/scs.2022.43.4.465.
  12. Francisco, J., Moreno, J., Filho, W. and Ruchert, C. (2016), "Effect of pre-crack in the fracture properties of steel pipes used in oil type API 5L X70", J. Braz. Soc. Mech. Sci. Eng., 38(7), 2117-2127. https://doi.org/10.1007/s40430-015-0469-3.
  13. Godefroid, L.B., Candido, L.C., Toffolo, R.V.B. and Barbosa, L.H.S. (2014), "Microstructure and mechanical properties of two API steels for iron ore pipelines", Mater. Res., 17(1), 114-120. https://doi.org/10.1590/S1516-14392014005000068.
  14. Hashemi, S.H., Sedghi, S., Soleymani, V. and Mohammadyani, D. (2012), "CTOA levels of welded joint in API X70 pipe steel", Eng. Fract. Mech., 82, 46-59. https://doi.org/10.1016/j.engfracmech.2011.11.022.
  15. Hassani, N., Kolbadi, S., Shiravand, M. and Golafshani, J. (2016), "Impact of geometric pattern corrosion on limit failure pressure of buried gas pipelines", Struct. Eng. Mech., 59(5), 795-802. https://doi.org/10.12989/sem.2016.59.5.795.
  16. Kang, W.H., Hicks, S.J., Uy, B. and Aslani, F. (2021), "Design resistance of helical seam pipe columns with limited tensile test data", J. Constr. Steel Res., 183, 106724. https://doi.org/10.1016/j.jcsr.2021.106724.
  17. Lee, J.S., Ju, J.B., Jang, J., Kim, W.S. and Kwon, D. (2004), "Weld crack assessments in API X65 pipeline: failure assessment diagrams with variations in representative mechanical properties", Mater. Sci. Eng. A, 373(1), 122-130. https://doi.org/10.1016/j.msea.2003.12.039.
  18. Li, D., Uy, B., Aslani, F. and Hou, C. (2019), "Behaviour and design of spiral-welded stainless steel tubes subjected to axial compression", J. Constr. Steel Res., 154, 67-83. https://doi.org/10.1016/j.jcsr.2018.11.029.
  19. Ligang, L., Hong, X., Qiang, L., Yu, L., Peishuai, L., Zhiqiang, Y. and Hui, Y. (2017), "Evaluation of the fracture toughness of X70 pipeline steel with ferrite-bainite microstructure", Mater. Sci. Eng. A, 688, 388-395. https://doi.org/10.1016/j.msea.2017.01.043.
  20. Manafi, H., Fakoor, F. and Fakoor, M. (2020), "Mixed mode I/II fracture criterion to anticipate behavior of the orthotropic materials", Steel Compos. Struct., 34(5), 671-679. https://doi.org/10.12989/scs.2020.34.5.671.
  21. Milne, I., Ainsworth, R.A., Dowling, A.R., Stewart, A.T. (1988), "Assessment of the integrity of structures containing defects", Int. J. Press. Vessel. Pip., 32(1), 3-104. https://doi.org/10.1016/0308-0161(88)90071-3.
  22. Park, D.Y., Gravel, J.P., Simha, H.M., Liang, J. and Duan, D.M. (2014), "Fracture toughness of X70 pipe girth welds using clamped SE(T) and SE(B) single-specimens", 10th International Pipeline Conference, Calgary, Alberta, Canada, October.
  23. Ramachandra Murthy, A., Vishnuvardhan, S., Saravanana, M. and Gandhi, P. (2022), "Prediction of stress intensity factor range for API 5L grade X65 steel by using GPR and MPMR", Struct. Eng. Mech., 81(5), 565-574. https://doi.org/10.12989/sem.2022.81.5.565.
  24. Teng, J.G. and Rotter, J.M. (2004), Buckling of Thin Metal Shells, Spon Press Taylor & Francis Group, London, UK.
  25. Torabi, A.R., Saboori, B. and Kamjoo, M.R. (2020), "Out-of-plane ductile failure of notch: Evaluation of Equivalent Material Concept", Struct. Eng. Mech., 75(5), 559-569. https://doi.org/10.12989/sem.2020.75.5.559.
  26. Vukelic, G. and Brnic, J. (2017), "Numerical prediction of fracture behavior for austenitic and martensitic stainless steels", Int. J. Appl. Mech., 9(4), 1750052. https://doi.org/10.1142/S1758825117500521.
  27. Yang, Y., Shi, L., Xu, Z., Lu, H., Chen, X. and Wang, X. (2015), "Fracture toughness of the materials in welded joint of X80 pipeline steel", Eng. Fract. Mech., 148, 337-349. https://doi.org/10.1016/j.engfracmech.2015.07.061.
  28. Zhou, D.W. (2011), "Measurement and modelling of R-curves for low-constraint specimens", Eng. Fract. Mech., 78(3), 605-622. https://doi.org/10.1016/j.engfracmech.2010.08.019.
  29. Zhu, X.K. and Joyce, J.A. (2012), "Review of fracture toughness (G, K, J, CTOD, CTOA) testing and standardization", Eng. Fract. Mech., 85, 1-46. https://doi.org/10.1016/j.engfracmech.2012.02.001.