PSI - Issue 14

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Rajwinder Singh et al. / Procedia Structural Integrity 14 (2019) 930–936 Author name / Structural Integrity Procedia 00 (2018) 000–000

935

da/dN ( m/cycle)

Fig. 5. Comparison of short fatigue crack growth rate da/dN as a function of crack length a in hydrogen charged and un-charged SA508 Gr. 3 Cl. I LAS specimens.

4. Conclusions The following conclusions are drawn from the experimental investigation of short fatigue crack propagation of un-charged and hydrogen charged specimens of SA508 Gr. 3 Cl. I LAS: 1. The short fatigue crack propagation rate in hydrogen charged SA508 Gr. 3 Cl. I LAS is one order higher as compared to the un-charged specimens. 2. Both inter-granular crack propagation through the prior austenite grains and trans-granular crack propagation along PAGBs are observed in hydrogen charged SA508 Gr. 3 Cl. I LAS, whereas only trans-granular crack propagation is observed in un-charged subject LAS. 3. The PAGBs offered very less resistance to short fatigue crack propagation in hydrogen charged SA508 Gr. 3 Cl. I LAS specimens whereas, PAGBs offered strong resistance to short fatigue crack propagation in un charged subject LAS. References Broomfield, G.H., 1965. Hydrogen effects in an irradiated 1% Cr, 1/2% Mo PWR pressure vessel steel. Journal of Nuclear Materials 16, 249–259. Chakravarny, J.K., Prasad, G.E., Sinha, T.K., Asundi, M.K., 1986. Hydrogen embrittlement of ASTM A 203 D nuclear structural steel. Journal of Nuclear Materials 138, 107–116. Huang, J.Y., Yeh, J.J., Kuo, R.C., Jeng, S.L., Young, M.C., 2008. Fatigue crack growth behavior of reactor pressure vessel steels in air and high-temperature water environments. International Journal of Pressure Vessels and Piping 85, 772–781. Kaynak, C., Ankara, A., Baker, T.J., 1996. A comparison of short and long fatigue crack growth in steel. International Journal of Fatigue 18, 17–23. Kim, M., Park, S., Lee, K., Lee, B., 2015. Comparison of fracture properties in SA508 Gr.3 and Gr.4N high strength