Investigations of underwater FHPP for welding steel overlap joints

Friction Hydro Pillar Processing (FHPP) is one of the most innovative friction welding processes. FHPP can be used under water whereby it can be employed to repair marine structures or undersea oil pipelines. Every new technique requires testing and further development and in the present case this was made possible by the PIPETAP research project sponsored by the European Community. The main idea of PIPETAP is to develop an advanced hot tapping system for operations on undersea deep-water oil and gas pipelines [ 1 ]. The system will also improve the safety and reduce the cost of onshore hot tapping operations. This report presents experimental work on a FHPP welding system, focusing on sleeve welds.