Effects of dissolved hydrogen and surface condition on the intergranular stress corrosion cracking initiation and short crack growth behavior of non-sensitized 316 stainless steel in simulated PWR primary water

Environmental correction factor (Fen) is one of the parameters to evaluate the effect of a pressurized high temperature water environment. It has been reported that Fen for stainless steel saturates at a very low strain rate. However, the relationship between environmentally assisted fatigue (EAF) and stress corrosion cracking (SCC) is still unclear. The aim of this study is to investigate the short crack growth behavior and possible continuity of EAF and SCC at very low strain rates. Short crack initiation and propagation have similar behaviors, which retard the crack growth between 100–200 μm in depth. We find that the striation spacing correlates well with the maximum crack growth rate (CGR) data. Based on the correlation, it is clarified that the local CGR on an intergranular facet was faster than that on a transgranular facet. Furthermore, the overall maximum and average CGR from the EAF data is well interpreted and compared with the SCC data.

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Experimental Study on Crack Growth Behavior for Austenitic Stainless Steel in High Temperature Pure Water

Journal of Pressure Vessel Technology ◽

10.1115/1.3264773 ◽

1986 ◽

Vol 108 (2) ◽

pp. 226-233 ◽

Cited By ~ 2

Author(s):

M. Hishida ◽

M. Saito ◽

K. Hasegawa ◽

K. Enomoto ◽

Y. Matsuo

Keyword(s):

Stainless Steel ◽

Crack Propagation ◽

Stress Corrosion ◽

Crack Growth ◽

Stress Corrosion Cracking ◽

Surface Crack ◽

Stress Ratio ◽

Growth Behavior ◽

Crack Growth Behavior ◽

Surface Crack Growth

Crack growth behavior of Type 304 stainless steel in a simulated BWR water environment was investigated for the quantitative characterization of subcritical flaw growth in BWR piping systems. Crack propagation rates under corrosion fatigue and stress corrosion cracking were generated using compact specimens. The effects of several parameters on the rates were discussed. Furthermore, surface crack growth behavior was examined under different modes of cyclic loading, and results were discussed in comparison with compact specimen data. The corrosion fatigue crack propagation rates strongly depended on the frequency and the stress ratio. The rates became higher as the frequency lowered and the stress ratio increased. No effect from dissolved oxygen concentration and heat treatment of the steel was observed in tests, where transgranular cracking mainly took place. Stress corrosion cracking rate data indicated KISCC was above 15 MPa•m1/2. On the other hand, surface crack growth behavior included scattered crack propagation rates. However, the relationship between da/dN and ΔK was basically similar to that obtained in the compact specimens, except under given test conditions, where the acceleration for the crack growth rate at a crack tip on the panel surface was different from that at the deepest point.

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