Journal of Mechanical Science and Technology

The Korean Society of Mechanical Engineers (대한기계학회)
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Creep Characterization of Type 316LN and HT-9 Stainless Steels by the K-R Creep Damage Model

  • Published : 2001.11.01
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Abstract

The Kachanov and Rabotnov (K-R) creep damage model was interpreted and applied to type 316LN and HT-9 stainless steels. Seven creep constants of the model, A, B, $textsc{k}$, m, λ, ${\gamma}$, and q were determine d for type 316LN stainless steel. In order to quantify a damage parameter, the cavity was interruptedly traced during creep for measuring cavity area to be reflected into the damage equation. For type 316LN stainless steel, λ= $\varepsilon$R/$\varepsilon$* and λf=$\varepsilon$/$\varepsilon$R were 3.1 and increased with creep strain. The creep curve with λ=3.1 depleted well the experimental data to the full lifetime and its damage curve showed a good agreement when r=24. However for the HT-9 stainless steel, the values of λ and λf were different as λ=6.2 and λf=8.5, and their K-R creep curves did not agree with the experimental data. This mismatch in the HT-9 steel was due to the ductile fracture by softening of materials rather than the brittle fracture by cavity growth. The differences of the values in the above steels were attributed to creep ductilities at the secondary and the tertiary creep stages.

Keywords

References

  1. Belloni, G., and Bernasconi, G., 1978, 'Creep Damage Models,' Creep of Engineering Materials and Structures, Edited by Bernasconi G. and Piatti G., Applied Science Publisher LTD, London, pp. 195-227
  2. Belloni, G., Bernasconi, G., and Piatti, G., 1977, 'Creep Damage and Rupture in AISI 310 Austenitic Steel,' Meccanica, Vol. 12, pp. 84-96 https://doi.org/10.1007/BF02215879
  3. Brathe, L., 1978, 'Macroscopic Measurements of Creep Damage in Metals,' Scand. J. Metallurgy, Vol. 7, pp. 199-203
  4. Cane, B.J., and Greenwood G. W., 1975, 'The Nucleation and Growth of Cavities in Iron during Deformation at Elevated Temperatures,' Metal Sci., Vol. 9, pp. 50-60
  5. Dysonm B. F., and McLean, D., 1972, 'A New Method of Predicting Creep Life,' Metal Science Journal, Vol. 6, pp. 220-223
  6. Kachanov, L. M., 1958, 'On Creep Rupture Time', Izv. ANSSSR, OTN, No. 8., pp. 26-31
  7. Kachanov, L. M., 1986, Introduction to Continuum Damage Mechanics, Martinus Nijhoff Publishers, Dordrecht, pp. 1-10
  8. Kim, W. G., Kim, D. W., and Ryu, W. S., 2000, 'Applicability of Monkman-Grant Relationships to Type 316L(N) Stainless Steel', Transactions of the KSME(A), Vol. 24, No. 9, pp. 2326-2333
  9. Kim, W. G., Kim. D. W., Ryu, W. S., and Kuk, I. H., 1998, 'Effect of Phosphorus on the Creep Properties in AISI 316L(N) Stainless Steel', Proc. of the Korean Nuclear Society Autumn Meeting, Seoul, pp. 216-221
  10. Kim, W. G., Kim. D. W., and Ryu, W. S., 2001, 'Creep Design of Type 316LN Stainless Steel by K-R Damage Model', Transactions of the KSME(A), Vol. 24, No. 2, pp. 296-303
  11. Kim, K. Y., and Lee, K. Y., 1996, 'The Life Assesment of Creep Damaged Components Used High Pressure and Temperature Condition by Metallographic Replicas', Proc. of Materials and Fracture Part of the KSME 96MF14, Seoul, pp. 90-96
  12. Leckie, F. A., and Hayhurst, D. R., 1975, 'The Damage Concept in Creep Mechanics', Mech. Res. Comm., Pergamon Press, Vol. 2, pp. 23-26 https://doi.org/10.1016/0093-6413(75)90020-8
  13. Leckie, F. A., and Hayhurst, D. R., 1977, 'Constitutive Equations for Creep Rupture', Acta Metallurgical, Vol. 25, pp. 1059-1070 https://doi.org/10.1016/0001-6160(77)90135-3
  14. Oh, Y. J., and Hong, J. H., 2000, 'Nitrogen Effect on Precipitation and Sensitization on Cold Worked Type 316L(N) Stainless Steels', Journal of Nuclear Materials, Vol. 278, pp. 242-250 https://doi.org/10.1016/S0022-3115(99)00255-X
  15. Penny, R. K., 1974, 'The Usefulness of Engineering Damage Parameters During Creep', Metal and Materials, Vol. 8, pp. 278-282
  16. Penny, R. K., and Marriott, D. L., 1995, Design for Creep, Chapman & Hall, London, pp. 165-174
  17. Rabotnov, Y. N., 1969, Creep in Structural Members, John Wiley & Sons, New York, pp. 359-382
  18. Riedel, H., 1987, Fracture at High Temperature, Springer-Verlag Berlin, Heidelberg, p. 390
  19. Ryu, W. S., Kim, W. G., Kim, D. W., Kuk, I. H., Kim, S. H., Jang, J. S., Rhee, C. K., Chung, M. G., Park, S. D., and Han, C. H., 1998, 'A State of the Art Report on LMR Structural Meterials', KAERI/AR-487/98, pp. 37-47
  20. Viswanathan, R., 1989, Damage Mechanisms and Life Assessment of High-Temperature Components, ASM International, Carnes Publication Services, Inc. Ohio, pp. 10-15