Evaluation of the Degradation Characteristics of CF-8A Cast Stainless Steel Using Indentation Techniques and EDS

Abstract:

Cast austenitic stainless steel piping pump, valve casings and elbows are susceptible to reductions in toughness and ductility because of long term exposure at the operating temperatures in the LWR (light water reactor). In this study, the three classes of thermally aged CF-8A cast austenitic stainless steel specimens were prepared using an artificially accelerated aging method for 0, 2,679 and 3,572 hours at 400oC. An indentation technique was applied to evaluate of the thermal aging of CF-8A cast austenitic stainless steel. We have performed indentation tests (automated ball indentation and nano-indentation) and EDS (energy dispersive spectroscopy) in order to characterize the micro-structural changes of the phase with aging. The fracture toughness of aged CF-8A cast stainless steel was determined by standard fracture toughness tests and automated ball indentation techniques.

• Periodical: Key Engineering Materials (Volumes 306-308)
• Pages: 869-874
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.306-308.869
• Online since: March 2006
• Authors: Seung Baek, Jae Mean Koo, Chang Sung Seok
• Keywords: Aging, Cast Austenitic Steel, CF-8A, Indentation

References

[1] Chopra, O.K., Chung, H.M.: Long term Embrittlement of Case Duplex Stainless Steels in LWR Systems", NUREG/CR-4744 Vol. 1, No. 2 (1986), ANL-87-16.

DOI: 10.2172/6673889

[2] Chopra, O.K., Sather, A.: Initial Assessment of the Mechanic and Significance of LowTemperature Embrittlement for Cast stainless Steels in LWR Systems, NUREG/CR-5385, ANL-89-17 (1990).

[3] Chopra, O.K.: Thermal Aging of Cast Stainless Steels in LWR Systems: Estimation of Mechanical Properties, Nuclear Plant System/ Components Aging Management and Life Extension, ASME, PVP Vol. 228 (1992), pp.79-92.

DOI: 10.2172/142528

[4] Shah, V.N., Macdonald, P.E.: Aging and Life Extension of major Light Water Reactor Components (1993), ELSEVIEAR, pp.146-186.

[5] Haggag, F. M., Murty, K. L., Liaw, P. K. : Non-destructive Evaluation and Materials Properties ( 1997), Warrendale, PA, USA.

[6] Mathew, M.D., Lietzan, L.M., Murty, K.L., Shah, V. N: Low Temperature Aging Embrittlement of CF-8 Stainless Steel, Material Science and Engineering, A269(1993) , p.186196.

DOI: 10.1016/s0921-5093(99)00140-9

[7] Seiichi, K., Naruo, S., Genta, T., Fukuhisa, M., Yasushi, K., L'ubos, M.: Microstructural changes and fracture behavior of CF-8M duplex stainless steels after long-term aging, Nuclear Engineering and design, 174(1997), pp.273-285.

DOI: 10.1016/s0029-5493(97)00126-x