| 朱天语,汪家梅,张乐福.冷变形和溶解氧对308L不锈钢焊材应力腐蚀开裂的影响规律[J].装备环境工程,2022,19(1):81-88. ZHU Tian-yu,WANG Jia-mei,ZHANG Le-fu.Effects of Cold Work and Dissolved Oxygen on Stress Corrosion Cracking of 308L Weld Metal[J].Equipment Environmental Engineering,2022,19(1):81-88. |
| 冷变形和溶解氧对308L不锈钢焊材应力腐蚀开裂的影响规律 |
| Effects of Cold Work and Dissolved Oxygen on Stress Corrosion Cracking of 308L Weld Metal |
| 投稿时间：2021-05-18 修订日期：2021-06-18 |
| DOI：10.7643/issn.1672-9242.2022.01.012 |
| 中文关键词: 308L 冷变形 溶解氧 高温高压水 应力腐蚀开裂 裂纹扩展速率中图分类号:TG172 TL341 文献标识码:A 文章编号:1672-9242(2022)01-0081-08 |
| 英文关键词:308L cold work dissolved oxygen high temperature high pressure water stress corrosion cracking crack growth rate |
| 基金项目:国家重点研发计划(2017YFB0702203) |
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| 中文摘要: |
| 目的 探究冷变形和溶解氧(DO)对308L不锈钢焊材在高温高压水环境中应力腐蚀开裂(SCC)行为的影响规律。方法 采用直流电压降法对308L试样裂纹扩展速率(CGR)进行在线测量，对比原始态、冷变形态308L焊材在DO和氢气除氧两种水环境中的SCC性能。参照F-A模型，结合冷变形前后材料微观组织和试样的断口形貌及裂纹扩展路径分析，给出冷变形和DO对308L焊材SCC影响规律的机理性解释。结果 原始态308L焊材具有较低的SCC敏感性，且在恒载荷下裂纹扩展容易停滞，断口主要呈现穿晶开裂形貌。20%冷变形可显著提高其CGR达1个数量级，断口呈现沿晶开裂形貌，且二次裂纹倾向于沿着δ-铁素体和γ-奥氏体相界面扩展。对于20%冷变形308L，DO可提高其CGR近2个数量级。结论 冷变形和DO均能显著提高308L的SCC敏感性。冷变形通过提高奥氏体枝晶的晶界和奥氏体-铁素体相界的残余应变而提高308L焊材的SCC敏感性；DO通过在尖端和基体间形成电势差，促进尖端微区水化学的酸化或碱化，加剧尖端金属溶解而加速裂纹扩展。 |
| 英文摘要: |
| 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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