油气管道剩余强度评价方法适用性研究

为了研究油气管道剩余强度评价方法的适用性，介绍了完整管道失效压力的计算方法以及NG-18，B31G，DNV RP-F101和PCORCC等4种计算含缺陷管道剩余强度的方法。对4种方法中的流变应力和膨胀系数进行了分析，同时采用4种计算方法计算了30组不同钢级管道的剩余强度。结果表明:流变应力的选取对中低强度钢管的影响较大，对中高强度钢管的影响较小，当管道钢级为X80及以上时，流变应力对剩余强度计算结果的影响可以忽略不计；各评价方法中，改进的B31G中的膨胀系数表达形式更加接近实际情况； NG-18和B31G适用于评价中低强度的钢管，其中，改进的B31G结果更为准确；DNV RP-F101和PCORCC适用于评价中高强度的钢管，其中，DNV RP-F101的计算结果优于PCORCC的计算结果；对于高钢级管道的评价方法还需要进一步研究和改进。

Research on applicability of evaluation method for residual strength of oil and gas pipeline

In order to study the applicability of evaluation method for residual strength of oil and gas pipeline, the calculation method on failure pressure of complete pipeline and four calculation methods on residual strength of pipeline containing defects, including NG-18, B31G, DNV RP-F101 and PCORCC, were introduced. The flow stress and expansion coefficient of the four methods were analyzed, and the residual strength of 30 groups of pipeline with different steel grades were calculated by using the four calculation methods. The results showed that the selection of flow stress has larger influence on the medium-low strength steel pipes, while the influence on the medium-high strength steel pipes is smaller. When the steel grade of pipeline is X80 or above, the influence of flow stress on the residual strength can be neglected. Among the evaluation methods, the expression form of expansion coefficient by the improved B31G is more close to the actual situation. NG-18 and B31G are applicable to the evaluation of medium-low strength steel pipes, and the evaluation results of modified B31G are more accurate. DNV RP-F101 and PCORCC are applicable to the evaluation of medium-high strength steel pipes, and the calculation results of DNV RP-F101 is better than that of PCORCC. The evaluation method for pipeline with high steel grade still need further research and improvement.