Influencing factors for improving accuracy in prediction of stress corrosion crack growth rate in boiling water reactor operational condition -1 prediction of SCC growth rate in terms of Vickers hardness

Yoichi Takeda, Zhanpeng Lu, Takeshi Adachi, Qunjia Peng, Jiro Kuniya, Tetsuo Shoji

研究成果: Conference contribution

抄録

It is known that stress corrosion cracking (SCC) found in the operational power plants show complex cracking behaviors and it's resulted in complex crack shape e.g. crack branching and its uneven crack front. For the cracking near the weldment, this is due to crack penetrated along the complex distribution of residual stress and strain hardened area. In this investigation, in order to advance the accuracy for crack growth prediction with considering such complex fields, theoretical formulation for SCC growth was further modified. Hardness of the materials, which is a measureable parameter even in operational power plant, was focused on to reflect strain hardening of the component like heat affected zone of the weldments. The theoretical formulation for SCC growth has terms with yield strength of the material and strain hardening exponent to describe crack tip strain rate. Strain hardening was simulated by cross rolling with the range of 4 - 32% as thickness reduction. Correlation between yield strength, strain hardening exponent at 288°C and Vickers hardness was obtained by means of tensile tests and hardness tests on 316L stainless steel. It was observed that a monotonic increase in Vickers hardness and yield strength with degree of reduction in thickness worked by cross rolling. Relationship between Vickers hardness and yield strength was found to have linear correlation. Further confirmation was made by plotting the reported mechanical properties data in terms of Vickers hardness. In addition, linear relationship was found between yield strength and strain hardening exponent. These relationships were introduced into SCC theoretical formulation and a SCC growth rate prediction curve in terms of Vickers hardness was proposed. SCC crack growth evaluation tests with selected work hardened 316L stainless steel were performed in oxygenated pure water environment at 288°C to confirm the predictability of the formulation. The prediction curve had a good agreement with available literature data as well as obtained crack growth rates in the hardness range of 140-300HV which was likely expected one in weld HAZ.

本文言語English
ホスト出版物のタイトルASME 2010 Pressure Vessels and Piping Division/K-PVP Conference, PVP2010
ページ969-976
ページ数8
DOI
出版ステータスPublished - 2010
イベントASME 2010 Pressure Vessels and Piping Division/K-PVP Conference, PVP2010 - Bellevue, WA, United States
継続期間: 2010 7 182010 7 22

出版物シリーズ

名前American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
1
ISSN(印刷版)0277-027X

Other

OtherASME 2010 Pressure Vessels and Piping Division/K-PVP Conference, PVP2010
国/地域United States
CityBellevue, WA
Period10/7/1810/7/22

ASJC Scopus subject areas

  • 機械工学

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