304 不锈钢在模拟深海和浅海环境中的应力腐蚀行为

目的研究304不锈钢在模拟深海和浅海中的应力腐蚀开裂(SCC)行为。方法通过控制不同环境因素模拟南海某海域环境,利用动电位扫描、交流阻抗谱、慢应变速率拉伸(SSRT)及SEM表面分析等手段进行研究。结果 304不锈钢在模拟海水溶液中呈现钝化状态,出现应力腐蚀敏感性,且裂纹扩展方式为穿晶开裂。在深海中的SCC机制为氢致开裂,浅海中的SCC机制主要为阳极溶解。结论 304不锈钢在深海与浅海中的SCC机制不同,但两者的SCC敏感性相近且相对较低,在模拟海水环境中的应用不受海水深度限制。

Stress Corrosion Behavior of 304 Stainless Steel in Simulated Deep and Shallow Seawater Environments

Objective To study the stress corrosion cracking (SCC) behavior of 304 stainless steel in simulated deep and shallow seawater environments. Methods The environment of a sea area in the South Sea was simulated by controlling different environmental factors, and potentiodynamic polarization, electrochemical impedance spectroscopy, slow strain rate test (SSRT) and superficial analysis technique using scanning electron microscope were applied for the research. Results 304 stainless steel exhibited a passivation behavior in the simulated seawater solution, and showed SCC susceptibility, besides, the crack propagation mode was transgranular cracking. The SCC mechanism in shallow sea was mainly controlled by anodic dissolution, while that in deep sea was controlled by hydrogen embrittlement. Conclusion Although 304 showed different SCC mechanisms in simulated deep sea and shallow sea, the SCC sensitivities were close and relatively low. So the use of 304 SS in simulated seawater environment was not limited by the depth of seawater.