Patent ID: 6429405
Filing Date: 2002-08-06
Classification: B23K

Abstract:
A method of forming a deep sea pipeline or a cross country pipeline including a step of welding two pipes together, said step of welding two pipes together comprising the steps of:arranging two pipes end to end, the pipes being so shaped that a circumferentially extending groove is defined between the ends of the pipes, the angle of separation of the walls defining the groove being less than 10 degrees, effecting relative movement of a plurality of arc welding torches arranged on a single carriage around the pipes and operating the torches so that their arcs form a weld in the groove, each torch being moved around the pipe with substantially the same component of velocity along the length of the groove, each torch being independently moved so that the respective positions of the arcs within the groove oscillate between the walls of the groove in a direction having a component parallel to the axis of the pipe, and automatically guiding the arc produced by each of the torches by ascertaining, in respect of an arc, electrical characteristics of the welding with regard to each pipe, respectively, and comparing the electrical characteristics relating to one of the pipes with the corresponding electrical characteristics relating to the other of the pipes.