X80管线钢管体缺陷极限承载能力

The ultimate bearing capacity of defects in X80 pipeline steel

目前含体积型缺陷管道的剩余强度评价标准和方法主要是针对X70及以下低钢级管线钢,而针对X80及以上高钢级管线钢的验证性试验很少。基于此,对比了不同管线钢管体缺陷的极限载荷评估模型及适用范围,管线钢通过对不同类型、不同尺寸缺陷的X80管线钢管进行水压试验,对各种评估模型在X80管线钢管上的适用性进行评价。结果表明:长矩形缺陷的承载能力在各类缺陷中最低,而且不同缺陷预测模型的安全程度不同;对于矩形缺陷,DNV模型的预测结果与试验值偏差较小,ASME B31G Modified、RSTRENG及C-FER模型的计算结果偏于安全;对于沟槽缺陷,C-FER和PDAM模型偏于安全;对于凹坑+沟槽缺陷,PDAM模型偏于安全。

As the current assessment criteria and methods for residual intensity of pipelines with volumetric defects are mainly based on X70 pipeline steel and the grades below it, and the verification tests on X80 pipeline steel and the grades above it are rarely conducted. Based on this, the ultimate loading assessment models for the defects in various pipeline steels and their application ranges were firstly compared. And then, various defects of different sizes were prepared in X80 pipe for hydrostatic burst tests to evaluate the applicability of various assessment models in X80 pipe. It is shown that among all defects, the long rectangular defect is usually the lowest in bearing capacity, and the safe degrees of different defect prediction models are different from each other. As for the rectangular defect, the prediction result of DNV model is the best accordant with the experimental value, and the calculation results of ASME B31G Modified, RSTRENG and C-FER models are relatively safe. As for the groove defect, C-FER and PDAM models are applicable. And PDAM model is also suitable for the pit ＋ groove defect. （6 Figures, 3 Tables, 23 References）