Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Round Robin Analyses on Stress Intensity Factors of Inner Surface Cracks in Welded Stainless Steel Pipes

  • Han, Chang-Gi (Department of Nuclear Engineering, College of Engineering, Kyung Hee University) ;
  • Chang, Yoon-Suk (Department of Nuclear Engineering, College of Engineering, Kyung Hee University) ;
  • Kim, Jong-Sung (Department of Mechanical Engineering, Sunchon National University) ;
  • Kim, Maan-Won (Central Research Institute, Korea Hydro & Nuclear Power Company)
  • Received : 2015.12.04
  • Accepted : 2016.05.24
  • Published : 2016.12.25
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Abstract

Austenitic stainless steels (ASSs) are widely used for nuclear pipes as they exhibit a good combination of mechanical properties and corrosion resistance. However, high tensile residual stresses may occur in ASS welds because postweld heat treatment is not generally conducted in order to avoid sensitization, which causes a stress corrosion crack. In this study, round robin analyses on stress intensity factors (SIFs) were carried out to examine the appropriateness of structural integrity assessment methods for ASS pipe welds with two types of circumferential cracks. Typical stress profiles were generated from finite element analyses by considering residual stresses and normal operating conditions. Then, SIFs of cracked ASS pipes were determined by analytical equations represented in fitness-for-service assessment codes as well as reference finite element analyses. The discrepancies of estimated SIFs among round robin participants were confirmed due to different assessment procedures and relevant considerations, as well as the mistakes of participants. The effects of uncertainty factors on SIFs were deducted from sensitivity analyses and, based on the similarity and conservatism compared with detailed finite element analysis results, the R6 code, taking into account the applied internal pressure and combination of stress components, was recommended as the optimum procedure for SIF estimation.

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References

  1. R.C. Wimpory, F.R. Biglari, R. Schneider, K.M. Nikbin, N.P. O'Dowd, Effect of residual stress on high temperature deformation in a weld stainless steel, Mater. Sci. Forum 524-525 (2006) 311-316. https://doi.org/10.4028/www.scientific.net/MSF.524-525.311
  2. H. Moshayedi, I. Sattari-Far, The effect of welding residual stresses on brittle fracture in an internal surface cracked pipe, Int. J. Press. Vessels Piping 126-127 (2015) 29-36. https://doi.org/10.1016/j.ijpvp.2015.01.003
  3. K. Chandra, V. Kain, V. Bhutani, V.S. Raja, R. Tewari, G.K. Dey, J.K. Chakravartty, Low temperature thermal aging of austenitic stainless steel welds: kinetics and effects on mechanical properties, Mater. Sci. Eng. A 534 (2012) 163-175. https://doi.org/10.1016/j.msea.2011.11.055
  4. P.K. Singh, V. Bhasim, R.K. Singh, R. Singh, G. Das, Low temperature thermal ageing embrittlement in austenitic stainless steel weld, Trans. Struct. Mech. Reactor Technol. 23 (2015) 305.
  5. K.S. Lee, W. Kim, J.G. Lee, Assessment of possibility of primary water stress corrosion cracking occurrence based on residual stress analysis in pressurizer safety nozzle of nuclear power plant, Nucl. Eng. Technol. 44 (2012) 343-354. https://doi.org/10.5516/NET.09.2010.066
  6. J.D. Hong, C.H. Jang, T.S. Kim, PFM application for the PWSCC integrity of Ni-base alloy weldsddevelopment and application of PINEP-PWSCC, Nucl. Eng. Technol. 44 (2012) 961-970. https://doi.org/10.5516/NET.07.2012.017
  7. T. Ogawa, M. Itatani, T. Saito, T. Hayashi, C. Narazaki, K. Tsuchihashi, Fracture assessment for a dissimilar metal weld of low alloy steel and Ni-base alloy, Int. J. Press. Vessels Piping 90-91 (2012) 61-68. https://doi.org/10.1016/j.ijpvp.2011.10.012
  8. S.H. Lee, Y.S. Chang, S.W. Kim, Residual stress assessment of nickel-based alloy 690 welding parts, Eng. Fail. Anal. 54 (2015) 57-73. https://doi.org/10.1016/j.engfailanal.2015.03.022
  9. ASME, ASME Boiler and Pressure Vessel Code, Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, App. A, 2010.
  10. American Petroleum Institute, API 579-1/ASME FFS-1, Fitness-for-Service, 2007.
  11. British Energy, R6-Assessment of the Integrity of Structures Containing Defects, Revision 4, 2010.
  12. S. Marie, C. Faidy, K.J. Bench, Benchmark on Analytical Calculation of Fracture Mechanics Parameters KI and J for Cracked Piping ComponentsdProgress of the Work, Proceedings of the ASME Pressure Vessels & Piping Conference PVP2013, 2013, p. 97178.
  13. KHNP, Standard Procedure for Finite Element Residual Stress Analysis, 2010.
  14. ASME, ASME Boiler and Pressure Vessel Code, Section II, Part D, Properties, 2004.
  15. AK Steel Corporation, 316/316L Stainless Steel Product Data Bulletin [Internet]. 2013 [cited 2014 Oct 28]. Available from: http://www.aksteel.com/pdf/markets_products/stainless/austenitic/316_316l_data_bulletin.pdf (accessed 28.10.14).
  16. M. Smith, A. Smith, NET Task Group 1 Single Weld Bead on Plate: Review of Phase 1 Weld Simulation Round Robin. Appendix AdProtocol for Finite Element Simulations of the NET Single-Bead-on-Plate Test Specimen, Report E/REP/BDBB/0089/GEN/05, British Energy Generation Ltd, 2006.
  17. Dassault Systems, ABAQUS, Version 6-13.1, 2013.