Steel and Composite Structures

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Yield strength estimation of X65 and X70 steel pipe with relatively low t/D ratio

  • Kim, Jungho (Department of Civil and Environmental Engineering, Seoul National University) ;
  • Kang, Soo-Chang (Steel Structure Research Group, POSCO) ;
  • Kim, Jin-Kook (Department of Civil Engineering, Seoul National University of Science and Technology) ;
  • Song, Junho (Department of Civil and Environmental Engineering, Seoul National University)
  • Received : 2019.07.24
  • Accepted : 2020.10.09
  • Published : 2021.01.25
⟨ Previous Next ⟩

Abstract

During the pipe forming process, a steel plate undergoes inelastic behavior multiple times under a load condition repeating tension and compression in the circumferential direction. It derives local reduction or increase of yield strength within the thickness of steel pipes by the plastic hardening and Bauschinger effect. In this study, a combined hardening model is proposed to effectively predict variations of yield strength in the circumferential direction of API-X65 and X70 steel pipes with relatively low t/D ratio during the forming process, which is expected to experience accumulated plastic strain of 2~3%, the typical Lüder band range in a low-carbon steel. Cyclic tensile tests of API-X65 and X70 steels were performed, and the parameters of the proposed model for the steels were calibrated using the test results. Bending-flattening tests to simulate repeated tension and compression during pipe forming were followed for API-X65 and X70 steels, and the results were compared with those by the proposed model and Zou et al. (2016), in order to verify the process of material model calibration based on tension-compression cyclic test, and the accuracy of the proposed model. Finally, parametric analysis for the yield strength of the steel plate in the circumferential direction of UOE pipe was conducted to investigate the effects of t/D and expansion ratios after O-forming on the yield strength. The results confirmed that the model by Zou et al. (2016) underestimated the yield strength of steel pipe with relatively low t/D ratio, and the parametric analysis showed that the t/D and expansion ratio have a significant impact on the strength of steel pipe.

Keywords

Acknowledgement

This study is financially supported by the research project of POSCO. The first and fourth authors are supported by the Institute of Construction and Environmental Engineering at Seoul National University. The supports are gratefully acknowledged.

References

  1. Alexandrov, E.S., Pirumov, R.A. and Jeng, R.Y. (2016), "Description of reversed yielding in thin hollow discs subjected to external pressure", Struct. Eng. Mech., 58(4), 661-676. https://doi.org/10.12989/sem.2016.58.4.661.
  2. API 5L (2007), Specification for Line Pipe. 44th edition, American Petroleum Institute; Washington (DC), USA.
  3. Chaboche, J.L. and Rousselier, G. (1983), "On the plastic and viscoplastic constitutive equations, Part 1: rules developed with internal variable concept", J. Press. Vess-T. ASME, 18(5-6), 153-158. https://doi.org/10.1115/1.3264257.
  4. Gao, Q., Lu, C., Li, H., Li, J., Han, J. and Chen, L. (2018), "Anisotropy and microstructural evolutions of X70 pipeline steel during tensile deformation", J. Mater. Res., 33(20), 3512- 3520. https://doi.org/10.1557/jmr.2018.190.
  5. Kim, H.L. and Park, S.H. (2020), "Loading direction dependence of yield-point phenomenon and bauschinger effect in API X70 steel sheet", Met. Mater. Int., 26(1), 14-24. https://doi.org/10.1007/s12540-019-00325-z.
  6. Kolasangiani, K., Farhangdoost, K., Shariati, M. and Varvani-Farahani, A. (2018), "Local ratcheting behavior in notched 1045 steel plates", Steel Compos. Struct., 28(1), 1-11. https://doi.org/10.12989/scs.2018.28.1.001.
  7. Kyriakides, S. and Corona, E. (2007), Mechanics of Offshore Pipeline, Vol 1: Buckling and Collapse, Elsevier, Oxford, UK.
  8. Nasrollahi, S., Maleki, S., Shariati, M., Marto, A. and Khorami, M. (2018), "Investigation of pipe shear connectors using push out test", Steel Compos. Struct., 27(5), 537-543. https://doi.org/10.12989/scs.2018.27.5.537.
  9. Ren, Q., Zou, T., Li, D., Tang, D. and Peng, Y. (2015), "Numerical study on the X80 UOE pipe forming process", J. Mater. Process. Tech., 215, 264-277. https://doi.org/10.1016/j.jmatprotec.2014.08.013.
  10. Rosado, D.B., Waele, W.D., Vanderschueren, D. and Hertele, S. (2013), "Latest developments in mechanical properties and metallurgical features of high strength line pipe steels", Int. J. Sustain. Constr. Design, 4(1). https://doi.org/10.21825/scad.v4i1.742.
  11. Sevim, B. (2017), "Structural response of rectangular composite columns under vertical and lateral loads", Steel Compos. Struct., 25(3), 287-298. https://doi.org/10.12989/scs.2017.25.3.287.
  12. Tan, Z., Magnusson, C. and Persson, B. (1994), "The Bauschinger effect in compression-tension of sheet metals", Mater. Sci. Eng.: A, 183(1-2), 31-38. https://doi.org/10.1016/0921-5093(94)90887-7.
  13. Toh, W., Tan, L.B., Tse, K.M., Raju, K., Lee, H.P. and Tan, V.B.C. (2018), "Numerical evaluation of buried composite and steel pipe structures under effects of gravity", Steel Compos. Struct., 26(1), 55-66. https://doi.org/10.12989/scs.2018.26.1.055.
  14. Wang, Y.B., Lyu, Y.F., Wang, Y.Z., Li, G.Q. and Liew, J.Y.R. (2020), "A reexamination of high strength steel yield criterion", Constr. Build. Mater., 230, 116945. https://doi.org/10.1016/j.conbuildmat.2019.116945.
  15. Yi, J., Kang, S.C., Koh, H.M. and Choo, J.F. (2018), "Yield strength prediction of UOE Pipes: From forming to flattening", Int. J. Offshore Polar Eng., 28(2), 206-211. https://doi.org/10.17736/ijope.2018.oa17.
  16. Yi, J., Kang, S.C., Park, W. and Choo, J. F. (2019), "Yield strength tracking of UOE pipe considering various thickness-to-diameter ratios", Mar. Struct., 68, 102616. https://doi.org/10.1016/j.marstruc.2019.04.004.
  17. Yoshida, F., Uemori, T. and Fujiwara, K. (2002), "Elastic-plastic behavior of steel sheets under in-plane cyclic tension-compression at large strain", Int. J. Plasticity, 18(5), 633-59. https://doi.org/10.1016/S0749-6419(01)00049-3.
  18. Zou, T., Wu, G., Li, D., Ren, Q., Xin, J. and Peng, Y. (2015), "A numerical method for predicting O-forming gap in UOE pipe manufacturing", Int. J. Mech. Sci., 98, 39-58. https://doi.org/10.1016/j.ijmecsci.2015.04.006.
  19. Zou, T., Li, D., Wu, G. and Peng, Y. (2016), "Yield strength development from high strength steel plate to UOE pipe", Mater. Design, 89, 1107-1122. https://doi.org/10.1016/j.matdes.2015.10.095.