Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Residual Stress in U-Bending Deformations and Expansion Joints of Heat Exchanger Tubes

전열관의 굽힘 및 확관접합 잔류응력

  • Published : 2000.02.01
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Abstract

Residual stress induced in U-bending and tube-to-tubesheet joint processes of PWR's row-1 heat exchanger tube was measured by X-ray method and Hole-Drilling Method(HDM). Compressive residual stresses(-) at the extrados surface were induced in U-bending, and its maximum value reached -319 MPa in axial direction at the position of $\psi$ = $0^{\circ}$. Tensile residual stresses(+) of $\sigma_{zz}$ = 45 MPa and $\sigma_{\theta\theta}$ = 25 MPa were introduced in the intrados surface at the position of $\psi$ = $0^{\circ}$. Maximum tensile residual stress of 170 MPa was measured at the flank side at the position of $\psi$ = $90^{\circ}$, i.e., at apex region. It was observed that higher stress gradient was generated at the irregular transition regions (ITR). The trend of residual stress induced by U bending process of the tubes was found to be related with the change of ovality. The residual stress induced by the explosive joint method was found to be lower than that by the mechanical roll method. The gradient of residual stress along the expanded tube was highest at the transition region (TR), and the residual stress in circumferential direction was found to be higher than the residual stress in axial direction.

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References

  1. Aspden, R.G., Carter, J.W. and L.P. Morgan, 1982, 'Cracking of Inconel 600 Steam Generator U-Bends from the Primary Side,' Corrosion 82, Huston Paper No. 206
  2. Randy, R. and Royer, D.V., 1983, 'Stress Corrosion Cracking of Inconel Alloy 600 in High Temperature Water -An Update,' Corrosion 83, California, April 18-22
  3. Yashima, S. and Uragami, K., 1982, 'Studies of Steam Generator U-Tubes Affecting Stress Corrosion Cracking,' ASME, Journal of Nuclear Material Paper No.82-NE-5
  4. Schoemeker, C.E., 1981, 'U- Bend Tube Cracking in Steam Generators,' Workshop Proceedings ; EPRI Project No. WS-80-136, June, pp. 9-1-33
  5. Berge, P.H., Bui, H.D., Donati, J.R. and Villard, D., 1976, 'Residual Stresses in Bent Tubes for Nuclear Steam Generators,' Corrosion-NACE, Vol. 32, No.9
  6. Ruud, C.O., 1987, 'Residual and Applied Stress analysis of an Alloy 600 Row 1 U-Bend,' EPRI Project No. NP-5282
  7. Pathania, R.S. and Lim, D., 'Stress Corrosion Cracking of Expanded Tube-to-Tubesheet Joints in Steam Generators,' Proc. of Int. Sympo. on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors, pp. 810-823
  8. Druez, J., Bazergui, A. and Pettigrew, M.J., 1985, 'Residual Stress in Roller-Expanded Thin Tubes,' Experimental Mechanics, September, pp. 316-324 https://doi.org/10.1007/BF02325104
  9. Gold, R.E., Pement, F.W., Tarabek, S.A. and Economy, G., 1991, 'The Resistance to PWSCC of Explosive Expanded Alloy 600 Tube-to-Tubesheet Joint,' Proc. of 5th Int. Sympo. on Enviromnmental Degradation of Materials in Nuclear Power Systems- Water Reactors, California, pp. 621-627
  10. Scott, D.A., Wolgemuyh, G.A. and Aikin, J.A., 1984, 'Hydraulically Expanded Tube-to-Tubesheet Joints,' Trans. ASME, Journal of Engineering Materials and Technology, Vol. 106, pp. 104-109
  11. Rigaku Corporation, 1994, 'Instruction manual for Residual Stress Analysis Program,' Manual No.ME201RF
  12. 박영철, 허선철, 부명환, 김현수, 강재욱, 1996, '세라믹/금속접합재의 고온역사이클에 따른 잔류응력분포 및 굽힘강도 특성,' 대한기계학회 논문집 A, 제21권 제10호, pp. 1541-1550
  13. Timoscchenko, S.P. and Goodier, J.N., Theory of Elasticity, 3rd ed., McGraw-Hill, pp. 90-97
  14. Schajer, G.S., 1988, 'Measurement of Non-Uniform Residual Stress Using the hole Drilling Method. Part I -Stress Calculation Procedures,' Trans. ASME. J. Eng. Mat. and Tech., Vol.110, pp. 338-349
  15. 주진원, 박찬기, 1997, '구멍뚫기방법을 이용한 잔류응력 측정에서의 유한요소법 이용,' 대한기계학회 '97 춘계학술대회 논문집 A, pp. 745-750
  16. 최병길, 이택순, 전상윤, 1990, '표면응력 구배시의 잔류응력 측정에 관한 연구,' 대한기계학회 논문집, 제 14권 제4호, pp. 761-768
  17. Micro-Measurment Group, 1988, 'Measurments of Residual Stress by the Hole-drilling Strain-Gage Method,' Measurment Group Tech Note TN-508-3
  18. ASTM, 1994, 'Standard Test Method of Determining Residual Stress by the Hole-Drilling Strain-Gage Method,' ASTM Standard E837-94a, pp. 1-7
  19. 1980, 'Inconel Alloy 690,' Huntingtoon Alloys, Inc.
  20. Joo, J.W. and Kwak, B.M., 1989, 'Simulation of Three-Point Bending at Large Deflections by an Elastoplastic Contact Analysis,' Experimemtal Mechanics, Vol. 29, No. 4, pp. 460-465 https://doi.org/10.1007/BF02323868
  21. Hosford, W.F. and Caddell, R.M., 1983, 'Metal Forming Mechanics and Metallurgy,' Chapter 12-Bending
  22. ASTM, 1986, 'Standard Specification for Seamless Nickel and Nickel Alloy Condenser and Heat Exchanger Tube,' ASTM B163-86a, pp. 62-71
  23. Rudd, C.O., Snoha, D.J., Ivkovich, D.P. and Mcllree, A.R., 1990, 'Residual Stresses in Inconel 600 U-Bend Heat Exchanger Tubes,' Journal of Pressure Vessel Technology, Vol. 112, pp. 169-174
  24. Srinivasan, R., Hartley, C.S. and Brandy, R., 1984, 'Residual Stress Determination in Inconel 600 Tubes using Electrochemical Machining,' Novel Techniques in Metal Deformation Testing, TMS-AIME Conf. Proc., pp. 163-174
  25. Druez, J. and Bazergui, A., 1983, 'Through-Thickness Measurement of Residual Stresses in Thin Tubes,' Experimental Mechanics, June, pp. 211-216 https://doi.org/10.1007/BF02320412