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介绍了输气管道几何凹坑缺陷的分类方法,比较分析了国外有关几何凹坑缺陷的评价方法,指出以几何凹坑最大深度和以几何凹坑在管道内外表面产生的最大应变为评价指标存在的不足,深入研究了Lukasiewicz-Czyz及Gao Ming等给出的等效应变表达式,将其计算结果分别与采用ASME B31.8标准推荐公式的计算结果相比较,结果表明:相对Lukasiewicz-Czyz公式所得值,利用ASME B31.8公式所得内表面等效应变低估了1倍,外表面等效应变低估了0.5倍;相对Gao Ming公式所得值,利用ASME B31.8公式计算所得内表面等效应变低估了2倍,外表面等效应变低估了0.2倍。给出了基于风险的几何凹坑缺陷处理程序及检测建议,对于保障我国天然气管道的安全运营,促进管道完整性管理的进步和完善具有一定意义。
The classification method of geometric pit defects in gas pipeline is introduced and the evaluation methods of geometric pit defects in foreign countries are comparatively analyzed. It is pointed out that the maximum depth of geometric pits and the maximum strain produced by geometric pits on the inner and outer surfaces of pipes are the evaluation indexes , The equivalent strain expressions given by Lukasiewicz-Czyz and Gao Ming et al. Are studied in depth. The calculated results are compared respectively with those calculated by the ASME B31.8 standard formula. The results show that compared with the Lukasiewicz-Czyz formula The values obtained from the ASME B31.8 formula underestimated the equivalent strain of the inner surface and the equivalent strain of the outer surface by 0.5 times. Compared with the value obtained from Gao Ming formula, the calculated equivalent strain of the inner surface Underestimated 2 times, the surface of the equivalent strain underestimated 0.2 times. The risk-based geometric pit defect processing program and testing suggestions are given, which is of great significance to guarantee the safe operation of natural gas pipeline in our country and to promote the improvement and perfection of pipeline integrity management.