通过对某长输天然气管道发生的爆炸事故进行详细的技术分析,确定了其发生爆管泄漏的原因和点火源。对爆裂管道的断口进行了宏观检查和测量,分析了断口宏观形貌;对发生爆裂和未发生爆裂的管道分别取样,进行化学成分分析和金相分析;沿爆裂管段横向取块状拉伸样品进行拉伸性能测试;对爆裂管道和未爆裂管道横截面进行显微硬度测试;在爆裂管道靠近划伤区域和未爆裂管道上分别取小块试样,进行金属内部氢含量测试;在扫描电镜下对断口进行观察。基于上述,确定了管道断裂原因,即管道表面严重划伤,造成管道发生氢致开裂,导致天然气泄漏,并与空气混合,形成爆炸性混合气体,遇供电线路绝缘子放电火花,发生爆炸火灾事故。最后从完整性管理、外防腐层检测、阴极保护等多个方面提出了有效的防范措施。(图11,表3,参6) Through a detailed technical analysis of the explosion accident occurred in a long-distance natural gas pipeline, the cause of the squib leak and the ignition source were confirmed. The fracture of the burst pipe was inspected and measured macroscopically, and the macroscopic appearance of the fracture was analyzed. The pipes which burst and did not burst were sampled respectively for chemical composition analysis and metallographic analysis. Tensile properties test; the burst pipe and non-burst pipe cross-section microhardness test; in the burst pipe near the scratch area and not burst pipe were taken small pieces of samples, the internal hydrogen content of metal testing; in the scanning electron microscopy Under the fracture to observe. Based on the above, the causes of pipeline fracture were confirmed, namely, the pipeline surface was severely scratched, resulting in hydrogen induced cracking in the pipeline, resulting in natural gas leakage and mixing with air to form an explosive mixture gas. In case of sparks from the insulator of the power supply line, an explosion and fire accident occurred. Finally, some effective precautionary measures are put forward from the aspects of integrity management, outer coating inspection and cathodic protection. (Figure 11, Table 3, reference 6)