通过断口分析、无损检测、力学试验和金相分析等手段研究了西部某油田处理站外输气弯管爆裂的原因。结果表明: 弯管外弧侧和断口处的显微组织全部为马氏体，导致该处抗拉强度和硬度大幅升高，表现出极大的脆性；在服役过程中，弯管外弧侧的微裂纹一旦扩展，马氏体相即表现出脆性开裂。

The reasons for gas transmission pipe bursting in a western oilfield were analyzed by fracture investigation, nondestructive testing, mechanical testing and metallographic analysis. The results show that the microstructure at the external arc side of the elbow and near the fracture area were martensite, which led to the substantial increase of tensile strength and hardness and showed great brittleness. During the service process, once those microcracks located at the external arc side of the elbow extended, martensite phase exhibited brittle cracking.