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| Effects of Cold Work and Dissolved Oxygen on Stress Corrosion Cracking of 308L Weld Metal |
| Received:May 18, 2021 Revised:June 18, 2021 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7643/issn.1672-9242.2022.01.012 |
| KeyWord:308L cold work dissolved oxygen high temperature high pressure water stress corrosion cracking crack growth rate |
| Author | Institution |
| ZHU Tian-yu |
School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai , China |
| WANG Jia-mei |
School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai , China |
| ZHANG Le-fu |
School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai , China |
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| Abstract: |
| This paper aims to study theinfluence laws of cold work and dissolve oxygen (DO) on the stress corrosion cracking (SCC) behavior of 308 L weld metal in high temperature water. SCC performance of 308L welding consumables in the original state and cold work state in DO and hydrogen deoxidized water environments are compared by using direct current potential drop (DCPD) to achieve on-line measurement of Crack Growth Rate (CGR) of 308 L Specimen. Referring to the F-A model, combined with the analysis of the microstructure of the material before and after cold work, and the fracture and crack propagation path analysis of the sample, the mechanical explanation of the influence of cold work and DO on the SCC of 308L welding consumables is given. The original 308 L welding material has low SCC sensitivity, and the crack growth is easy to stagnate under constant load, and the fracture mainly presents a transgranular cracking morphology. 20% cold work can significantly increase its CGR by an order of magnitude; the fracture exhibits an intergranular cracking morphology, and secondary cracks tend to propagate along with the interface of δ-ferrite and γ-austenite. For 20% cold work 308L, DO can improve its CGR by nearly 2 orders of magnitude. Both cold work and DO can significantly improve the SCC susceptibility of 308L. cold work improves the SCC sensitivity of 308L welding consumables by increasing the residual strain at the grain boundaries of austenite dendrites and austenite-ferrite phase boundaries; DO promotes the formation of a potential difference between the tip and the matrix to promote water in the tip micro-region. Chemical acidification or alkalization aggravates the dissolution of the tip metal and accelerates crack propagation. |
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