Browse > Article
http://dx.doi.org/10.3365/KJMM.2011.49.12.924

Evaluation of Creep-Fatigue Damage in 304 Stainless Steel using Ultrasonic Non-Destructive Test  

Lee, Sung Sik (Safetech Co. Ltd.)
Oh, Yong Jun (Div. of Adv. Mater. Eng., Hanbat National Univ.)
Nam, Soo Woo (KISTI ReSEAT Program)
Publication Information
Korean Journal of Metals and Materials / v.49, no.12, 2011 , pp. 924-929 More about this Journal
Abstract
It is well known that grain boundary cavitation is the main failure mechanism in austenitic stainless steel under tensile hold creep-fatigue interaction conditions. The cavities are nucleated at the grain boundary during cyclic loading and grow to become grain boundary cracks. The attenuation of ultrasound depends on scattering and absorption in polycrystalline materials. Scattering occurs when a propagation wave encounters microstructural discontinuities, such as internal voids or cavities. Since the density of the creep-fatigue cavities increases with the fatigue cycles, the attenuation of ultrasound will also be increased with the fatigue cycles and this attenuation can be detected nondestructively. In this study, it is found that individual grain boundary cavities are formed and grow up to about 100 cycles and then, these cavities coalesce to become cracks. The measured ultrasonic attenuation increased with the cycles up to cycle 100, where it reached a maximum value and then decreased with further cycles. These experimental measurements strongly indicate that the open pores of cavities contribute to the attenuation of ultrasonic waves. However, when the cavities develop, at the grain boundary cracks whose crack surfaces are in contact with each other, there is no longer any open space and the ultrasonic wave may propagate across the cracks. Therefore, the attenuation of ultrasonic waves will be decreased. This phenomenon of maximum attenuation is very important to judge the stage of grain boundary crack development, which is the indication of the dangerous stage of the structures.
Keywords
alloys; non-destructive test; defects; scanning electron microscopy (SEM); creep-fatigue;
Citations & Related Records

Times Cited By SCOPUS : 1
연도 인용수 순위
  • Reference
1 B. G. Choi, Y. C. Yoon, J. M. Lee, and S. W. Nam, J. Kor. Inst. Met. Mater. 32, 683 (1994).
2 B. G. Choi, Y. C. Yoon, J. J. Kim, and S. W. Nam, J. Mater. Sci. 31, 4957 (1996).   DOI   ScienceOn
3 S. W. Nam, Y. C. Yoon, B. G. Choi, J. M. Lee, and J. W. Hong, Metall. Mater. Trans. A 27A, 1273 (1996).
4 J. W. Hong, S. W. Nam, and K-T. Rie, J. Mater. Sci. 20, 3763 (1985).   DOI   ScienceOn
5 S. W. Nam, Y. C. Yoon, B. G. Choi, and J. J. Kim, J. Mater. Sci. 31, 4957 (1996).   DOI   ScienceOn
6 E. G. Ellison and A. J. F. Paterson, Proc. Inst. Mech. Eng. 190, 333 (1976).
7 C. R. Brinkman, G. E. Korth, and R. R. Hobbins, Nuclear Tech. 16, 297 (1972).   DOI
8 J. B. Conway and J. T. Berling, Metall. Trans. A 1A, 324 (1970).
9 J. B. Conway, J. T. Berling, and R. H. Stentz, Metall. Trans. A 8, 3247 (1971)
10 Nondestructive Evaluation of Materials Properties Korea Research Institute of Standards and Science Report, p. 8-9 (1995).
11 A. Vary, Materials Evaluation 46, 642 (1988).
12 R. Klinman, G.R. Webster, F. J. Marsh, and E. T. Stephenson, Material Evaluation Oct., 26 (1980)
13 R. Klinman and E. T. Stephenson, Materials Evaluation 39, 1116 (1981).
14 R. L. Smith, Ultrasonics Sep., 211 (1982).
15 R. L. Smith, W. N. Reynolds, and H. N. G. Wadly, Metal Science 15, 554 (1981).   DOI
16 C. F. Ying and Rohn Truell, J. Appl. Physics 27, 1086 (1956).   DOI
17 C. M. Sayers, J. Phys. D: Appl. Phys. 14, 413 (1981).   DOI   ScienceOn
18 C. M. Sayers and R. L. Smith, Ultrasonics Sep., 201 (1982).
19 Yong Jun Oh, Joong-Cheul Park, and Won Jon Yang, Kor. J. Met. Mater. 49, 541 (2011).   DOI   ScienceOn