Homopolar Pulsed Welding of API Line Pipe

Homopolar pulse welding is a welding process that is being developed to rapidly join API line pipe. This process has particular potential for application in offshore pipeline construction utilizing the J lay method. The weld joint produced has high strength and a narrow heat affected zone. There is a thin brittle zone at the weld interface, resulting in low impact toughness. The weld line is characterized by a very thin >light band>, believed to be a ferrite rich zone produced by a combination of localized melting and mechanical upset. Current developmental research is progressing to eliminate this brittle zone and improve weld geometry