Development of In-Service Weld Repair Method for L555 (X80)-Grade Pipeline

This paper deals with the development of the overlay weld repair method and the weld sleeve repair method applicable to L555 (X80) pipeline. Mechanical properties of the repaired pipes were investigated and finally proper welding materials and conditions were determined which could ensure hardness limit, required strength and toughness for in-service weld repair methods. Applicability of the in-service repair methods was validated and it was consequently confirmed that the weld repair methods will be able to apply to the repair of operating or pressurized pipeline ensuring the integrity of pipeline.