| Popis: |
The burst failure of a high frequency welded (HFW) pipe used for nature gas pipeline in an oilfield was analyzed systematically by macro analysis, physical and chemical property test, scanning electron microscope (SEM), etc., and the limit internal pressure of the pipeline under operation condition was predicted based on finite element method (FEM). The results showed that the chemical composition and mechanical properties of the pipe meet the requirements of relevant standards. The failure results showed that the dent damage of the straight pipe section was at 12 o'clock. In the service of the pipeline, the stress in the dent area exceeds the yield strength, which leads to the plastic deformation of the pipeline, resulting in necking and thinning, and the reduction of wall thickness further leads to the decrease of ultimate internal pressure, until the ultimate bearing capacity of the dent area is less than the internal pressure of pipeline operation, resulting in burst. It is suggested to strengthen the supervision of pipeline construction to avoid the pipeline dent damage. Meanwhile, the operation monitoring of the pipeline with dent damage should be strengthened, and timely repair or depressurization operation should be carried out if necessary. |
