Influence of wall thickness error on bearing capacity of seamless pipeline

Baiyunebo Iron Slurry Pipeline Engineering of Baotou Steel Works was built by X65 seamless steel pipeline with a diameter of 355.6×15.5 mm. In order to understand the impact law of wall thickness errors in the bearing capacity of pipeline, analytical method based on Yu Hongmao Unified Strength Theory was used to calculate the elastic limit and plastic limit solution of the pipeline and the redundancy between them. The impact of the material strength parameters and tension-compression ratio on ultimate bearing capacity of the pipeline were also analyzed. The results showed that the analytic solution contained the ratio of wall thickness and square of diameter could reflect the impact of wall thickness and diameter on the elastic limit of bearing capacity more accurately. The elastic limit of bearing capacity of the pipeline accorded with the design pressure of 16 MPa and test pressure of 28.2 MPa. The minimum wall thickness of 14.3 mm met the requirements of safety. Improving the toughness of steel could increase the bearing capacity of the pipeline. The redundancy between the elastic limit and plastic limit was about 8%. The results indicated that considering the wall thickness error of the pipeline sufficiently and taking the elastic limit as design criterion could improve the safety and reliability of the pipeline.