一起氨制冷系统管道断裂事故的原因分析

The Causes Analyses of A Ammonia Refrigeration System Pipeline Fracture Accident

制冷系统的库房回气管道发生了断裂失效,断裂位置在环焊缝中心且断口平整,焊缝存在未焊透缺陷。管道采用管束整体发泡保温,增加了管道的刚性,不利于管道的位移补偿。通过对管道材质进行分析,化学成分和力学性能符合设计要求。对管道受力状态进行分析并进行应力计算,结果表明,管道焊接接头未焊透,削弱了焊接接头的承载能力。管道在"冷缩"时不能补偿而产生较大的拉应力,导致在管道强度薄弱的焊接接头处发生断裂失效。

The fracture failure occurred in the suction pipe of the cold store refrigeration system,the fracture position was in the center of the circular weld,the fracture surface was smooth and there existed defects of not welded thoroughly. Pipe bundle heat insulation used overall foam,the rigidity of the pipeline was increased,but not conducive to the displacement compensation of the pipeline. Through the analysis of the material of the pipe,chemical composition and mechanical properties met the design requirements. The stress state of the pipeline was analyzed and the stress calculated. The results showed that the pipe welding joint was not welded thoroughly,and the weakened of the welded joint was weakened. When the pipeline was ‘cold shrinkage＇,it wouldn＇t compensate and lead to tensile stress,fracture failure occurred at the weld joint where the strength of the pipeline was weak.