FV520B钢在H_2S/CO_2环境下的应力腐蚀

采用慢应变速率应力腐蚀拉伸试验方法,开展了FV520B钢在模拟管道压缩机叶轮腐蚀介质环境中的高温、高压应力腐蚀开裂(SCC)研究,探讨了H2S浓度、CO2浓度、温度、压力等环境参数对FV520B钢应力腐蚀开裂的影响规律和作用机制.试验结果表明,H2S起主要腐蚀作用,应力腐蚀敏感指数随H2S浓度的增加而增大,而压力在一定范围内对应力腐蚀敏感指数影响不大.通过试样断口微观形貌观察分析,研究其应力腐蚀行为和机理,并计算不同环境参数下的应力腐蚀敏感指数,运用回归分析方法建立了FV520B钢在H2S/CO2环境中应力腐蚀敏感指数与介质浓度、温度、压力等环境参数之间的数学模型,表明H2S浓度、温度对应力腐蚀敏感指数的影响较为显著,同时,4种参数对应力腐蚀敏感指数产生交互作用.

Stress Corrosion Behavior of FV520B Steel in H2S/CO2 Environment

Based on simulating corrosion environments of centrifugal compressor for natural gas pipe line ， the stress corrosion cracking (SCC) of FV520B steel was studied by slow strain rate testing (SSRT) method， and the effecting law and action mechanism of concentration of H₂S and CO₂， temperature and pressure on the SCC were discussed. The results show that H₂S plays a major role on the corrosion， the stress corrosion sensitivity index (I_S) increases with the increase of concentration of H₂S， while the stress in certain range has little effect. We researched the corrosion behavior of FV520B steel by analyzing the micro fracture morphology， calculated the I_S in different environment parameters. Finally， the mathematical model of the environment parameters and the I_S of FV520B was established with the regression analysis method. The model shows that the influence of H₂S concentration and temperature on the I_S is significant， and four parameters have interaction on the I_S.