TY - JOUR
T1 - Effects of loading mode and water chemistry on stress corrosion crack growth behavior of 316L HAZ and weld metal materials in high temperature pure water
AU - Lu, Zhanpeng
AU - Shoji, Tetsuo
AU - Takeda, Yoichi
AU - Ito, Yuzuru
AU - Kai, Akira
AU - Tsuchiya, Nobuhisa
N1 - Funding Information:
This work was performed as a part of the Reliability Centred Life Prediction of Environmentally Assisted Cracking (PEACE III) program jointly supported EDF, EPRI, SKI, TEPCO, KEPCO, TohokuEPCO, JAPCO, HITACHI Ltd., MHI, TOSHIBA Co., and IHI. A part of this work was also carried out under the contract of Japan Nuclear Energy Safety Organization (JNES) project on IGSCC, which was supported by the Ministry of Economy, Trade and Industries (METI) in Japan. A part of this work has been performed under the support of Grant-in-Aid for Scientific Research (S) 17106002, Japan Society for the Promotion of Science, and the support of Grant-in-aid for the 21st Century COE program, “The Exploration of the Frontiers of Mechanical Science Based on Nanotechnology”, by the Japanese Ministry of Education, Culture, Sports, Science and Technology. Their supports are gratefully acknowledged. The assistance from H. Komatsu in the experiments is also gratefully acknowledged.
PY - 2008/3
Y1 - 2008/3
N2 - The stress corrosion cracking (SCC) growth rates of 316L weld heat-affected zone (HAZ) and weld metal materials in high temperature pure water at 288 °C were measured using contoured double cantilever beam (CDCB) specimens and an alternating current potential drop (ACPD) in situ crack-length monitoring system. The effects of loading mode and dissolved oxygen and hydrogen on crack growth rate (CGR) were experimentally quantified. Typical intergranular SCC was found in the HAZ specimen and interdendritic SCC was identified in the weld metal specimen. The HAZ specimen and the weld metal specimen showed quite a similar response to the applied loading modes and the water chemistry, even though their absolute CGR values were different. The crack growth rates under trapezoidal loading were moderately higher than those under constant loading by several tenths percent. Switching the water chemistry from the oxygen-bearing water to the hydrogen-bearing water drastically decreased the electrochemical potential and the crack growth rate, and vice versa. A time-lag period for crack growth was observed after switching the water chemistry back to the oxygen-bearing water, where the crack growth rate was low even the dissolved oxygen concentration and the electrochemical potential had become high. Strain hardening and the resultant uneven distribution of deformation contribute to the enhanced intergranular SCC growth behavior in the HAZ area. The crack growth kinetics is analyzed based on the deformation/oxidation interaction at the crack tip, considering the importance of the electric-charge transfer, mass transport kinetics and the crack tip strain rate.
AB - The stress corrosion cracking (SCC) growth rates of 316L weld heat-affected zone (HAZ) and weld metal materials in high temperature pure water at 288 °C were measured using contoured double cantilever beam (CDCB) specimens and an alternating current potential drop (ACPD) in situ crack-length monitoring system. The effects of loading mode and dissolved oxygen and hydrogen on crack growth rate (CGR) were experimentally quantified. Typical intergranular SCC was found in the HAZ specimen and interdendritic SCC was identified in the weld metal specimen. The HAZ specimen and the weld metal specimen showed quite a similar response to the applied loading modes and the water chemistry, even though their absolute CGR values were different. The crack growth rates under trapezoidal loading were moderately higher than those under constant loading by several tenths percent. Switching the water chemistry from the oxygen-bearing water to the hydrogen-bearing water drastically decreased the electrochemical potential and the crack growth rate, and vice versa. A time-lag period for crack growth was observed after switching the water chemistry back to the oxygen-bearing water, where the crack growth rate was low even the dissolved oxygen concentration and the electrochemical potential had become high. Strain hardening and the resultant uneven distribution of deformation contribute to the enhanced intergranular SCC growth behavior in the HAZ area. The crack growth kinetics is analyzed based on the deformation/oxidation interaction at the crack tip, considering the importance of the electric-charge transfer, mass transport kinetics and the crack tip strain rate.
KW - A. 316L weld heat-affected zone
KW - A. 316L weld metal
KW - A. Simulated boiling water reactor environment
KW - C. Crack growth rate
KW - C. Stress corrosion cracking
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U2 - 10.1016/j.corsci.2007.08.021
DO - 10.1016/j.corsci.2007.08.021
M3 - Article
AN - SCOPUS:39749151162
SN - 0010-938X
VL - 50
SP - 625
EP - 638
JO - Corrosion Science
JF - Corrosion Science
IS - 3
ER -