目的 揭示硫酸盐还原菌（SRB）在管线钢表面裂纹萌生中的作用。方法 采用恒载荷实验装置施加弹性和塑性应力，通过XPS和EDS分析产物成分，利用SEM观察微生物膜形态、管线钢腐蚀形貌，研究弹性和塑性应力作用下管线钢的微生物致裂裂纹萌生和扩展行为。结果 弹性和塑性应力对SRB生长无明显影响。不管是在弹性应力还是塑性应力作用下，SRB生理活动均改变了腐蚀产物的结构，增加了腐蚀产物的硫含量，提高了管线钢局部腐蚀敏感性。与弹性应力作用相比，塑性应力和SRB协同作用对管线钢微裂纹萌生和扩展的影响更大。塑性应力作用下，灭菌和接菌环境中管线钢表面均产生了微裂纹分叉。结论 弹性应力和塑性应力均促进了管线钢的微生物腐蚀过程。塑性应力作用下管线钢菌致开裂更加剧烈，裂纹扩展过程与SRB生理活动有关。

The work aims to discover the role of SRB in crack initiation of pipeline steel. The elastic and plastic stresses were applied via a constant-load set-up. The components of corrosion products were detected by XPS and EDS. The biofilm morphologies and the corrosion morphologies of pipeline were observed by SEM to study the initiation and propagation of mi-cro-cracks of pipeline steel under elastic and plastic stresses. Elastic and plastic stresses had no significant effect on SRB growth. Regardless of the actions under elastic stress or plastic stress, the SRB physiological activities changed the structure and increased the sulfur content of corrosion products and enhanced the local corrosion sensitivity of the steel. The synergistic effect of plastic stress and SRB, had greater influence on the initiation and propagation of micro-cracks in the steel compared with that of elastic stress and SRB. Under the action of plastic stress, micro-cracks bifurcated on the pipeline steel in both the sterilization and SRB-inoculated soil solutions. Both the elastic and plastic stresses can promote the corrosion process of the pipeline steel. The bacteria assisted cracking becomes more severe under the action of the plastic stress. The micro-crack propagation of the steel is related to the physiological activity of SRB.