NDTnet 1998 Aug, Vol.3 No.8

Abstract

Fig.

This EC supported project will develop underwater Friction Stitch Welding for the repair of fatigue cracks in offshore steel structures. SCS were one of the sponsors (with several UK oil companies,and the Pressure Products Group) of the fundamental development of this process done at The Welding Institute in Cambridge.

The main advantages of this welding system are:

• It can be used directly in sea water without a dry welding habitat, producing welds of the same quality as dry welds.
• It is not effected by increased pressure (depth) so there would be no need for hyperbaric welding procedure tests as is presently required with dry hyperbaric or wet welding.
• There is no depth limit to the use of the system. (Hyperbaric Electric Arc welding may not operate deeper than about 2000 m).
• The system will be much less complicated to mechanise and control than Electric Arc welding.

The repair system will include Eddy Current or ACFM sensors, MPI Systems and ultrasonic sensors for positioning of the welding head and verification of the welding result. All systems will be rated for deepwater remote application.

The project will develop a prototype friction stitch welding head and an underwater electric robot arm on which to deploy it.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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