Continuity of Environmentally Assisted Fatigue and Stress Corrosion Cracking Based on Short Crack Growth Behavior of 316 Stainless Steel in Simulated PWR Primary Water

2017 ◽  
Author(s):  
Choongmoo Shim ◽  
Yoichi Takeda ◽  
Tetsuo Shoji
Keyword(s):  
Stainless Steel ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Water Environment ◽  
Growth Behavior ◽  
Corrosion Cracking ◽  
Short Crack ◽  
Crack Growth Behavior ◽  
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.

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

1986 ◽  
Vol 108 (2) ◽  
pp. 226-233 ◽  
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.

532 Evaluation of crack growth behavior by stress corrosion cracking based on non-linear fracture mechanics

2013 ◽  
Vol 2013.62 (0) ◽  
pp. 323-324
Author(s):  
Naohiro SHIZUOKA ◽  
Tomoyuki FUJII ◽  
Keiichiro TOHGO ◽  
Yoshinobu SHIMAMURA ◽  
Masahiro TAKANASHI ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Growth Behavior ◽  
Corrosion Cracking ◽  
Crack Growth Behavior ◽  
Linear Fracture Mechanics ◽  
Linear Fracture ◽  
Non Linear

CRACK GROWTH BEHAVIOR FOR STRESS CORROSION CRACKING OF 690 ALLOY IN HIGH TEMPERATURE WATER

2011 ◽  
Vol 46 (10) ◽  
pp. 1267-1274 ◽  
Author(s):  
Tichun DAN ◽  
Zhanpeng LU ◽  
Jianqiu WANG ◽  
Enhou HAN ◽  
SHOJI Testuo ◽  
...  
Keyword(s):  
High Temperature ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Growth Behavior ◽  
Corrosion Cracking ◽  
Crack Growth Behavior ◽  
High Temperature Water ◽  
Temperature Water

Simulation of Stress Corrosion Cracking in ICM Housing of Nuclear Power Plant

2012 ◽  
Author(s):  
Masanori Kikuchi ◽  
Yoshitaka Wada ◽  
Kazuhiro Suga ◽  
Fuminori Iwamatsu ◽  
Yuichi Shintaku
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Growth Behavior ◽  
Corrosion Cracking ◽  
Stress Fields ◽  
Crack Growth Behavior ◽  
Residual Stress Field

It has been reported that stress corrosion cracking damaged in-core monitor housing (ICM Housing), which occurred in a weld heat-affected zone because of the existence of residual stress. So it is important to evaluate crack growth behavior with high accuracy. In this study, crack growth behavior in ICM Housing is estimated using S-version FEM (S-FEM), which allows generation of the core finite model and the detailed mesh representing the crack independently. At first, axial, slant and circumferential surface cracks are assumed at two locations where residual stress fields are different from each other. One is isotropic residual stress field, and the other is circumferential residual stress field. It is shown that crack growth behaviors are different under different residual stress fields. Next, the effect of the slit, which exists between the ICM Housing and the Pressure Vessel is evaluated. It is shown that the existences of the slit increases stress intensity factors of growing surface crack. Finally S-FEM results are compared with those of the Influence Function Method (IFM), which assumes that an elliptical crack shape exists in a plate. It is shown that IFM result is conservative comparing to that of S-FEM.

Weld Residual Stresses and Primary Water Stress Corrosion Cracking in Bimetal Nuclear Pipe Welds

2007 ◽  
Author(s):  
Frederick W. Brust ◽  
Paul M. Scott
Keyword(s):  
Water Stress ◽  
Residual Stresses ◽  
Weld Metal ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Pressure Vessel ◽  
Large Diameter ◽  
Corrosion Cracking ◽  
Primary Water

There have been incidents recently where cracking has been observed in the bi-metallic welds that join the hot leg to the reactor pressure vessel nozzle. The hot leg pipes are typically large diameter, thick wall pipes. Typically, an inconel weld metal is used to join the ferritic pressure vessel steel to the stainless steel pipe. The cracking, mainly confined to the inconel weld metal, is caused by corrosion mechanisms. Tensile weld residual stresses, in addition to service loads, contribute to PWSCC (Primary Water Stress Corrosion Cracking) crack growth. In addition to the large diameter hot leg pipe, cracking in other piping components of different sizes has been observed. For instance, surge lines and spray line cracking has been observed that has been attributed to this degradation mechanism. Here we present some models which are used to predict the PWSCC behavior in nuclear piping. This includes weld model solutions of bimetal pipe welds along with an example calculation of PWSCC crack growth in a hot leg. Risk based considerations are also discussed.

Failure Probability Analysis Based on FRI Model for Stress Corrosion Cracking Growth Introducing Residual Stress Distribution by Weld

2012 ◽  
Author(s):  
Noriyoshi Maeda ◽  
Tetsuo Shoji
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stress Distribution ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Failure Probability ◽  
Corrosion Cracking ◽  
Protective Film

Failure probability of welds by stress corrosion cracking (SCC) in austenitic stainless steel piping is analyzed by a probabilistic fracture mechanics (PFM) approach based on an electro-chemical crack growth model (FRI model, where FRI stands for “Fracture and Reliability Research Institute” of Tohoku University in Japan). In this model, crack growth rate da/dt, where a is crack depth, is anticipated as the rate of chemical corrosion process defined by electro-chemical Coulomb’s law. The process is also related to the strain rate at the crack tip, taking the small scale yielding into consideration. Compared to the mechanical crack growth equation like the power law for SCC, FRI model can introduce many parameters affecting the generation and break of protective film on the crack surface such as electric current associated with corrosion, the frequency of protective film break and mechanical parameters such as the stress intensity factor K and its change with time dK/dt. Derived transcendental equation is transformed into non-dimensional form, and then solved numerically by iterative method. The extension of surface crack by SCC under residual stress field is simulated by developing the stress distribution in polynomial form following ASME section XI appendix A. This simulation scheme is introduced into PFM framework to derive the failure probability of austenitic stainless steel piping in nuclear power plants to be used in developing a risk-informed inservice inspection (RI-ISI) program.

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