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油、气长输和集输管道在试压时,管道的某处曾经受了较高的压力,而在其它处发生破裂,而不得不将管线减压,并对缺陷部位修补后,再重新升压时,就在这曾经受了较高压力之处却在低于以前的压力下发生破裂现象,在国外文献中称这种现象为承压能力逆转(Pressure Reversal)。笔者从力学的观点对这种“承压能力逆转”现象进行了分析:认为管材的断裂韧性、裂纹的形状、循环压力水平及压力保持时间都是影响裂纹的增长和承压能力逆转的主要因素。提出了采用较高的试验压力进行分段试压以及对于间歇输送的管道应把压力或应力限制在稳定扩展曲线以下,即采用高试验压力,低操作压力,增大安全系数的办法来减少承压能力逆转和裂纹稳定扩展的工程措施。
Oil, gas long-distance lose and gathering pipe in the pressure test, somewhere in the pipeline had been subjected to high pressure, and rupture in other places, and had to decompress the pipeline, and repair the defect site, and then re- When the pressure was raised, the rupture happened under the pressure which was once higher but the pressure was reversed in foreign literature (Pressure Reversal). The author from the mechanical point of view of this “reversible pressure” phenomenon was analyzed: that the fracture toughness of the pipe, the shape of the crack, the pressure level and cycle pressure to maintain pressure are the main factors that affect the crack growth and pressure reversal . Proposed to use higher test pressure for sub-pressure test and for intermittent pipeline pressure or stress should be limited to the stability of the expansion curve below, that is, the use of high test pressure, low operating pressure, increase the safety factor approach to reduce bearing Engineering practice of reversing the pressure capability and stabilizing the crack growth.