Experiences in welding the Turkish stream gas pipeline and interconnector Serbia - Bulgaria

Abstract

The gas pipeline "Turski Tok" was built in the period from 2019 to 2021 with a total length of 403 km (Zaječar-Horgoš). The pipeline has a capacity of up to 15 billion cubic meters, a diameter of 1219 mm and its thickness is 14.27 mm. The steel L485MEPSL2 was used for production. The Serbia Bulgaria interconnector is 109 km long (Niš-Sofia), with a capacity of 1.8 billion cubic meters of gas, a diameter of 711 mm and the thickness is 8.7 mm. Steel X52 was used for its construction. Different procedures were used for welding: • Welding E111 (cellulose and basic coating), • MAG 135 with welding of the root of the welded joint with a semiautomatic device STT, and filling with an automatic procedure with two devices, • Welding with the MAG process of the root of the welded joint on the inside, using the internal centralizer, and on the outside with the automatic MAG process with two devices, • Welding from the outside with automatic MAG process with two devices, Self-Shielded Flux Cored Arc Welding wire FCAW-114 using an internal centralizer with a copper ring. The paper presents experiences with gas pipeline welding, with a critical review of selected solutions and suggestions for optimizing welding technology.