Girth welding procedure and weldability evaluation of coal seam gas transmission UOE pipeline

According to the requirements of Queensland Gas Company Ltd. (QGC) ,the operator of the Queensland Curtis LNG (QCLNG) pipeline project in Australia, girth welding experiments and weldability evaluations have been carried out for three X70 UOE pipes from Baosteel based on API 1104 standards. Shielded metal arc welding (SMAW) and gas-shielded flux-cored wire arc welding (FCAW-G) have been applied, and the girth weld joint quality and mechanical performance were evaluated. It was found that the field girth weldability of Baosteel's X70 UOE pipes was excellent under the conditions used here and satisfied the requirements of the QCLNG project for field girth welding construction. Furthermore, Baosteel has offered a solution to the QCLNG project for pipeline girth welding in which the girth welding joint design, selection of welding processes and consumables, welding procedures, techniques and joint inspections are included. Such research provides important guidance for the difficult tie-in welding applications for the construction of the QCLNG pipelines in the field.