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Tetsuo Shoji - One of the best experts on this subject based on the ideXlab platform.
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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
Corrosion Science, 2017Co-Authors: Xiangyu Zhong, Shirish Chandrakant Bali, Tetsuo ShojiAbstract:Abstract The effects of dissolved hydrogen (DH) and inner surface finish condition of the hollowed specimen on Stress Corrosion Crack (SCC) initiation and small Crack growth behaviors of 316 stainless steel were investigated in high temperature water with various DH levels. The drilled specimen showed higher surface hardness and more enhanced SCC initiation and short Crack growth behavior than honed specimen but both showed a similar trend in the water chemistry with different DH levels. Fractographic examinations showed mixed modes of transgranular and intergranular Cracking. The influences of DH and surface condition on SCC behaviors are discussed.
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environmentally assisted Crack growth in one dimensionally cold worked alloy 690tt in primary water
Corrosion Science, 2012Co-Authors: Qunjia Peng, Tetsuo Shoji, Juan Hou, Toshio Yonezawa, Zhaoen Zhang, Fa Huang, En-hou HanAbstract:Abstract Environmentally assisted Crack growth in thermally treated Alloy 690 cold worked one-dimensionally to the thickness reduction of 25% in primary water was investigated. In the water at 50 °C and dissolved hydrogen (DH) of 2.7–2.9 ppm, the alloy showed a Crack growth rate of −9 mm/s at a Stress intensity factor of 35 MPa√m. In the water at 340 °C, Stress Corrosion Crack growth rate of −8 mm/s was observed in the alloy over a DH range of 0.37–2.6 ppm. Further, it was found that hydrogen could promote SCC growth when increasing DH from a very low level.
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the effect of roll processing orientation on Stress Corrosion Cracking of warm rolled 304l stainless steel in oxygenated and deoxygenated high temperature pure water
Corrosion Science, 2010Co-Authors: Zhanpeng Lu, Tetsuo Shoji, Toshio YonezawaAbstract:Stress Corrosion Crack growth rates of 304L stainless steel after one-directionally warm-rolled along the longitudinal (L) direction were measured in oxygenated and deoxygenated pure water at 288 °C. The fracture mode is mainly intergranular in the Transverse-longitudinal (T-L) orientation specimen, while it is occasionally intergranular in the Longitudinal-transverse (L-T) orientation specimen. The Crack growth rates in the T-L orientation are higher than those in the L-T orientation in both oxygenated and deoxygenated environments, which is related to the effective Cracking growth path as the result of microstructural anisotropy and applied loading direction.
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Formulating Stress Corrosion Cracking growth rates by combination of Crack tip mechanics and Crack tip oxidation kinetics
Corrosion Science, 2010Co-Authors: Tetsuo Shoji, Zhanpeng Lu, Hiroyoshi MurakamiAbstract:A theoretical equation for Stress Corrosion Crack growth rate of austenitic alloys in high temperature water is reformulated based on Crack tip asymptotic fields and Crack tip transient oxidation kinetics. A general oxidation kinetic law is introduced, emphasizing the role of mass transport through solid oxide film at the Crack tip. The effects of several parameters on Crack growth rate are evaluated. The results are compared with available experimental data and other equations. A good prediction of the effect of K on Stress Corrosion Cracking growth rate of typical austenitic alloys in simulated light water reactor environments has been achieved.
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The Crack Tip Solution Chemistry in Sensitized Stainless Steel in Simulated Boiling Water Reactor Water Studied Using a Microsampling Technique
Journal of Nuclear Science and Technology, 2003Co-Authors: Qunjia Peng, Tetsuo ShojiAbstract:In order to obtain a better understanding of the mechanism of Stress Corrosion Cracking, an improved microsampling technique was applied to measurements of the local solution chemistry at the growing tip of a Stress Corrosion Crack. Efforts were made to improve the microsampling technique to obtain more accurate information about the Crack tip solution chemistry and apply it to measurements of the Crack tip solution chemistry in sensitized 304L stainless steel in simulated Boiling Water Reactor water. The improved technique was used to study the effects of dissolved oxygen, testing temperature and exposure time on the concentration of harmful anions at the Crack tip. The microsampled solution from the Crack tip was analyzed by a Capillary Electrophoresis system. The results as well as the effects of the improved technique were discussed.
Qunjia Peng - One of the best experts on this subject based on the ideXlab platform.
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environmentally assisted Crack growth in 308l stainless steel weld metal in simulated primary water
Corrosion Science, 2017Co-Authors: Lijin Dong, Qunjia Peng, En-hou Han, Lei WangAbstract:Abstract Environmentally assisted Crack growth behavior of 308L stainless steel weld metal in simulated primary water was investigated. The results showed ultra-low Stress Corrosion Crack growth in the weld metal. However, obvious environmental acceleration of fatigue Crack growth was observed, which is increased by more aggressive water chemistry and gentle cyclic loading conditions. Further, the environmental fatigue Crack growth rate of 308L weld metal was lower than that of 304 and 316 stainless steels under the same environmental and loading conditions. This was attributed to the retardation of Crack growth by δ ferrite phase.
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Stress Corrosion Cracking in the heat affected zone of a stainless steel 308L-316L weld joint in primary water
Corrosion Science, 2016Co-Authors: Lijin Dong, Qunjia Peng, Wei Ke, En-hou Han, Lei WangAbstract:Stress Corrosion Cracking (SCC) in the heat affected zone (HAZ) of a stainless steel 308L-316L weld joint in primary water of pressurized water reactor was investigated. Stress Corrosion Crack growth in the HAZ was observed in off-normal primary water chemistry with dissolved oxygen, but not in normal primary water chemistry with dissolved hydrogen. This suggests that it is unlikely a Stress Corrosion Crack propagating in the HAZ could reach the fusion boundary and penetrate into the weld metal under normal primary water chemistry conditions. Microstructure analysis of the Crack tip suggests that the SCC follows the slip-oxidation mechanism.
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environmentally assisted Crack growth in one dimensionally cold worked alloy 690tt in primary water
Corrosion Science, 2012Co-Authors: Qunjia Peng, Tetsuo Shoji, Juan Hou, Toshio Yonezawa, Zhaoen Zhang, Fa Huang, En-hou HanAbstract:Abstract Environmentally assisted Crack growth in thermally treated Alloy 690 cold worked one-dimensionally to the thickness reduction of 25% in primary water was investigated. In the water at 50 °C and dissolved hydrogen (DH) of 2.7–2.9 ppm, the alloy showed a Crack growth rate of −9 mm/s at a Stress intensity factor of 35 MPa√m. In the water at 340 °C, Stress Corrosion Crack growth rate of −8 mm/s was observed in the alloy over a DH range of 0.37–2.6 ppm. Further, it was found that hydrogen could promote SCC growth when increasing DH from a very low level.
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The Crack Tip Solution Chemistry in Sensitized Stainless Steel in Simulated Boiling Water Reactor Water Studied Using a Microsampling Technique
Journal of Nuclear Science and Technology, 2003Co-Authors: Qunjia Peng, Tetsuo ShojiAbstract:In order to obtain a better understanding of the mechanism of Stress Corrosion Cracking, an improved microsampling technique was applied to measurements of the local solution chemistry at the growing tip of a Stress Corrosion Crack. Efforts were made to improve the microsampling technique to obtain more accurate information about the Crack tip solution chemistry and apply it to measurements of the Crack tip solution chemistry in sensitized 304L stainless steel in simulated Boiling Water Reactor water. The improved technique was used to study the effects of dissolved oxygen, testing temperature and exposure time on the concentration of harmful anions at the Crack tip. The microsampled solution from the Crack tip was analyzed by a Capillary Electrophoresis system. The results as well as the effects of the improved technique were discussed.
Gary S Was - One of the best experts on this subject based on the ideXlab platform.
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a high resolution characterization of the initiation of Stress Corrosion Crack in alloy 690 in simulated pressurized water reactor primary water
Corrosion Science, 2020Co-Authors: Wenjun Kuang, Gary S WasAbstract:Abstract Stress Corrosion Crack initiation of alloy 690 in simulated pressurized water reactor primary water was studied through high-resolution characterization of grain boundaries at different stages of the initiation process. It was found that a compact layer of Cr2O3 initially forms over a migrated grain boundary, driven by the diffusion of Cr. After the surface Cr2O3 is breached by straining, oxygen diffusion results in formation of a mixture of NiO and Cr2O3 along the grain boundary. The Crack nucleates along either the previous grain boundary or the heavily oxidized migration zone when the boundary strength falls below the local Stress.
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Stress Corrosion Crack initiation in alloy 690 in high temperature water
Current Opinion in Solid State & Materials Science, 2018Co-Authors: Tyler Moss, Wenjun Kuang, Gary S WasAbstract:Abstract Initiation of Stress Corrosion Cracks in Alloy 690 in high temperature water is a rare occurrence and depends on the method by which the sample is loaded. Only in dynamic straining experiments is Crack initiation consistently observed. Stress relaxation in constant deflection tests, and lack of a means of rupturing the oxide film in constant load tests are the principle reasons for the difficulty of initiating Cracks in these tests. These observations, combined with those from the much more susceptible Alloy 600 form the basis for a mechanism Stress Corrosion Crack (SCC) initiation of Alloy 690. SCC initiation is proposed to occur in three stages: an oxidation stage in which a protective film of Cr2O3 is formed on the surface over grain boundaries, an incubation stage in which successive cycles of oxide film rupture and repair depletes the grain boundary of chromium, and a nucleation stage in which the chromium depleted grain boundary is no longer able to support growth of a protective chromium oxide layer, resulting in formation and rupture of oxides down the grain boundary. The mechanism is supported by the available literature on oxidation and Crack initiation of Alloy 690 in hydrogenated primary water conditions.
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microstructural study on the Stress Corrosion Cracking of alloy 690 in simulated pressurized water reactor primary environment
18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors 2017, 2017Co-Authors: Wenjun Kuang, Miao Song, Chad M Parish, Gary S WasAbstract:This study was aimed at investigating the intergranular attack near a Stress Corrosion Crack (SCC) of alloy 690 in simulated pressurized water reactor (PWR) primary water environment. Solution annealed alloy 690 was evaluated for its SCC initiation susceptibility in 360 °C hydrogenated pure water using slow strain rate tensile technique. After the test, a grain boundary showing SCC initiation was sampled with Focused Ion Beam (FIB) milling. The microstructure and elemental distribution near the Crack tip were studied using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The results show that intergranular oxidation occurs ahead of the Crack tip and is preceded by diffusion induced grain boundary migration. The oxides at the Crack tip are mainly composed of NiO and Cr2O3 which maintain rigid orientations with the neighboring grains. The adjacent migration zone is free of oxidization as a compact layer of Cr2O3 dominates at the oxide/substrate interfaces and the very tip region.
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mechanism of dislocation channel induced irradiation assisted Stress Corrosion Crack initiation in austenitic stainless steel
Current Opinion in Solid State & Materials Science, 2015Co-Authors: Michael D Mcmurtrey, I M Robertson, Diana Farkas, Bai Cui, Gary S WasAbstract:Abstract The mechanism by which dislocation channeling induces irradiation assisted Stress Corrosion Cracking was determined using Fe–13Cr15Ni austenitic stainless steel irradiated with protons to a dose of 5 dpa and strained at high temperature in both argon and simulated boiling water reactor normal water chemistry environments. Straining induced dislocation channels that were characterized by digital image correlation and confocal microscopy. Dislocation channels were found to be either continuous across the boundary, discontinuous, or discontinuous with slip in the boundary. Discontinuous channels were found to contain the least amount of strain but have the highest propensity for initiating Cracks. Discontinuous dislocation channel–grain boundary intersections were shown to have the highest local Stress. TEM in-situ straining of irradiated steels and atomistic simulation of dislocation–grain boundary interaction provided supporting evidence that channels that were unable to transfer strain underwent Cracking. The inability of channels to relieve Stress, by either slip in the adjacent grain or in the grain boundary, resulted in high local Stresses and increased susceptibility to Stress Corrosion Cracking initiation.
Wenjun Kuang - One of the best experts on this subject based on the ideXlab platform.
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insight into the acceleration in oxidation kinetics ahead of Stress Corrosion Crack of alloy 690 in simulated pwr primary water
Corrosion Science, 2020Co-Authors: Wenjun Kuang, Miao Song, Xingyu FengAbstract:Abstract The acceleration in oxidation kinetics beyond a Stress Corrosion Crack of alloy 690 in simulated PWR primary water was clarified by comparing the oxide depths at two identical carbide/matrix interfaces along a single grain boundary. Compact chromia layer formed along these two interfaces at vastly different rates. Stress concentration ahead of the Crack tip only slightly increased the oxidation rate as the Crack is still very shallow. Deformation localization near the Crack plays a dominant role in accelerating oxidation kinetics as the associated high vacancy concentration can promote the diffusivity of oxygen by over an order of magnitude.
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international round robin on Stress Corrosion Crack initiation of alloy 600 material in pressurized water reactor primary water
Corrosion, 2020Co-Authors: P J Meadows, Stefan Ritter, Wenjun Kuang, Peter L Andresen, Mychailo B Toloczko, M Bjurman, Lefu Zhang, M Ernestova, Aki Toivonen, F PerosanzlopezAbstract:The International Cooperative Group on Environmentally Assisted Cracking of Water Reactor Materials coordinated an international “Round-Robin” collaboration of 10 laboratories on Stress Corrosion c...
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a high resolution characterization of the initiation of Stress Corrosion Crack in alloy 690 in simulated pressurized water reactor primary water
Corrosion Science, 2020Co-Authors: Wenjun Kuang, Gary S WasAbstract:Abstract Stress Corrosion Crack initiation of alloy 690 in simulated pressurized water reactor primary water was studied through high-resolution characterization of grain boundaries at different stages of the initiation process. It was found that a compact layer of Cr2O3 initially forms over a migrated grain boundary, driven by the diffusion of Cr. After the surface Cr2O3 is breached by straining, oxygen diffusion results in formation of a mixture of NiO and Cr2O3 along the grain boundary. The Crack nucleates along either the previous grain boundary or the heavily oxidized migration zone when the boundary strength falls below the local Stress.
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Stress Corrosion Crack initiation in alloy 690 in high temperature water
Current Opinion in Solid State & Materials Science, 2018Co-Authors: Tyler Moss, Wenjun Kuang, Gary S WasAbstract:Abstract Initiation of Stress Corrosion Cracks in Alloy 690 in high temperature water is a rare occurrence and depends on the method by which the sample is loaded. Only in dynamic straining experiments is Crack initiation consistently observed. Stress relaxation in constant deflection tests, and lack of a means of rupturing the oxide film in constant load tests are the principle reasons for the difficulty of initiating Cracks in these tests. These observations, combined with those from the much more susceptible Alloy 600 form the basis for a mechanism Stress Corrosion Crack (SCC) initiation of Alloy 690. SCC initiation is proposed to occur in three stages: an oxidation stage in which a protective film of Cr2O3 is formed on the surface over grain boundaries, an incubation stage in which successive cycles of oxide film rupture and repair depletes the grain boundary of chromium, and a nucleation stage in which the chromium depleted grain boundary is no longer able to support growth of a protective chromium oxide layer, resulting in formation and rupture of oxides down the grain boundary. The mechanism is supported by the available literature on oxidation and Crack initiation of Alloy 690 in hydrogenated primary water conditions.
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microstructural study on the Stress Corrosion Cracking of alloy 690 in simulated pressurized water reactor primary environment
18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors 2017, 2017Co-Authors: Wenjun Kuang, Miao Song, Chad M Parish, Gary S WasAbstract:This study was aimed at investigating the intergranular attack near a Stress Corrosion Crack (SCC) of alloy 690 in simulated pressurized water reactor (PWR) primary water environment. Solution annealed alloy 690 was evaluated for its SCC initiation susceptibility in 360 °C hydrogenated pure water using slow strain rate tensile technique. After the test, a grain boundary showing SCC initiation was sampled with Focused Ion Beam (FIB) milling. The microstructure and elemental distribution near the Crack tip were studied using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The results show that intergranular oxidation occurs ahead of the Crack tip and is preceded by diffusion induced grain boundary migration. The oxides at the Crack tip are mainly composed of NiO and Cr2O3 which maintain rigid orientations with the neighboring grains. The adjacent migration zone is free of oxidization as a compact layer of Cr2O3 dominates at the oxide/substrate interfaces and the very tip region.
En-hou Han - One of the best experts on this subject based on the ideXlab platform.
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environmentally assisted Crack growth in 308l stainless steel weld metal in simulated primary water
Corrosion Science, 2017Co-Authors: Lijin Dong, Qunjia Peng, En-hou Han, Lei WangAbstract:Abstract Environmentally assisted Crack growth behavior of 308L stainless steel weld metal in simulated primary water was investigated. The results showed ultra-low Stress Corrosion Crack growth in the weld metal. However, obvious environmental acceleration of fatigue Crack growth was observed, which is increased by more aggressive water chemistry and gentle cyclic loading conditions. Further, the environmental fatigue Crack growth rate of 308L weld metal was lower than that of 304 and 316 stainless steels under the same environmental and loading conditions. This was attributed to the retardation of Crack growth by δ ferrite phase.
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Stress Corrosion Cracking in the heat affected zone of a stainless steel 308L-316L weld joint in primary water
Corrosion Science, 2016Co-Authors: Lijin Dong, Qunjia Peng, Wei Ke, En-hou Han, Lei WangAbstract:Stress Corrosion Cracking (SCC) in the heat affected zone (HAZ) of a stainless steel 308L-316L weld joint in primary water of pressurized water reactor was investigated. Stress Corrosion Crack growth in the HAZ was observed in off-normal primary water chemistry with dissolved oxygen, but not in normal primary water chemistry with dissolved hydrogen. This suggests that it is unlikely a Stress Corrosion Crack propagating in the HAZ could reach the fusion boundary and penetrate into the weld metal under normal primary water chemistry conditions. Microstructure analysis of the Crack tip suggests that the SCC follows the slip-oxidation mechanism.
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environmentally assisted Crack growth in one dimensionally cold worked alloy 690tt in primary water
Corrosion Science, 2012Co-Authors: Qunjia Peng, Tetsuo Shoji, Juan Hou, Toshio Yonezawa, Zhaoen Zhang, Fa Huang, En-hou HanAbstract:Abstract Environmentally assisted Crack growth in thermally treated Alloy 690 cold worked one-dimensionally to the thickness reduction of 25% in primary water was investigated. In the water at 50 °C and dissolved hydrogen (DH) of 2.7–2.9 ppm, the alloy showed a Crack growth rate of −9 mm/s at a Stress intensity factor of 35 MPa√m. In the water at 340 °C, Stress Corrosion Crack growth rate of −8 mm/s was observed in the alloy over a DH range of 0.37–2.6 ppm. Further, it was found that hydrogen could promote SCC growth when increasing DH from a very low level.