Degradation mechanisms and evaluation of failure of gas pipelines

Abstract

This paper presents the degradation mechanisms and their effect on lifetime of Gas Transmission Pipelines (GTP). The degradation mechanisms of US, Europe, Russian and Lithuanian GTP are presented. Lithuanian GTP is described in more detail. The experimental testing of mechanical properties and fracture parameters of selected pipelines were carried out. The fracture mechanic analysis was performed for segment of gas transmission pipeline of Lithuania. The acceptable and critical cracks sizes were determined. Also Stress Corrosion Cracking (SCC) mechanism was analysed and cracks sizes at witch SCC could be expected were determined. For simulation of defects R6 option 1 method was used.