在模拟油田CO₂/H₂S共存环境中, 利用高温高压模拟试验、四点弯曲应力加载方法及扫描电子显微镜分析评价了13Cr不锈钢在模拟油田环境中应力和缝隙协同作用下的应力腐蚀敏感性。结果表明: 在CO₂和H₂S环境中无应力条件下, 13Cr不锈钢均有稳定的阳极钝化区, 但环境中出现H₂S后, 其自腐蚀电位明显降低, 腐蚀速率相对增大, 点蚀敏感性增大, 加载应力(80% σ_s)后, 材料表面钝化状态不稳定; 在H₂S分压为0.1 MPa的高温高压环境中, 当加载80% σ_s应力并协同0.1 mm缝隙作用时, 13Cr不锈钢表面缝隙处出现了点蚀现象, 但并未扩展导致应力腐蚀开裂; 当H₂S分压增大至0.5 MPa并加载80% σ_s应力时, 试样发生应力腐蚀开裂。H₂S的存在增大了材料表面的活性, 促进腐蚀损伤的加速。

In CO₂/H₂S coexisting environment simulating oil field, the stress corrosion sensitivity of 13Cr stainless steel under the interaction of stress and crevice in simulated oilfield environment was evaluated by means of high temperature and high pressure simulation test, four-point bending stress loading method and scanning electron microscopy. The results show that under stress-free condition in CO₂ and H₂S environments the 13Cr stainless steel had stable anodic passivation zones. But the corrosion potential was significantly reduced when H₂S occurred in the environment, the corrosion rate and pitting corrosion sensitivity were relatively increased, and the passivation state of the material surface was unstable after loading stress (80% σ_s). In a high temperature and high pressure environment at H₂S partial pressure of 0.1 MPa and under the interaction of 80% σ_s stress and 0.1 mm crevice, pitting corrosion appeared in the crevices on the surface of 13Cr stainless steel, but did not expand to cause stress corrosion cracking. When the partial pressure of H₂S increased to 0.5 MPa, stress corrosion cracking occurred when stress of 80% σ_s was loaded. The presence of H₂S increased the activity of the material surface and accelerated the corrosion damage.