The design for the fracture toughness of girth weld in China-Russia Eastern Gas Pipeline

The fracture toughness of girth weld is the key factor to ensure its safety.In China, the fracture toughness of pipeline girth weld is mainly determined in reference to the toughness index of steel pipe body weld, without theoretical calculation and technical support at present.Based on the principle of fracture mechanics, the Engineering Critical Assessment (ECA) based on Fitness-for-Service stipulated in the BS 7910-2013 to methods for assessing the acceptability of flaws in metallic structures is adopted to calculate the critical fracture toughness under which the weld is not fractured in the designed working condition of China-Russia Eastern Gas Pipeline by analyzing the stress and allowable ultimate defect size.Then, based on the values stipulated in current domestic and foreign standards and specifications, it is determined that the average absorption energy of 3specimens in each group of girth weld impact energy is 50 J, and the minimum value of single specimen is 38 J in the ChinaRussia Eastern Gas Pipeline project.Hence, the on-site construction difficulty is reduced while the safety of pipeline girth weld is guaranteed.The research results provide the guidance and reference for the determination of girth weld impact energy in similar engineering in the future.