Wet Welding has in former times only been applied to secondary structural components. Nowadays wet welding has become an upcoming repair process due to high process flexibility, its low investment costs and its high versatility. Even the quality of the wet welded Joints has been improved remarkably due to intensive and concentrated development activities. However, especially in the North Sea regions owners of offshore structures and classifying authorities still hesitate to recognize the process as a reliable alternative to dry hyperbaric welding repair methods. It therefore requires further acclivities especially in the field of data development for life prediction of such repaired components. Advanced telling methods are necessary, additional design criteria are to be developed and achievable weldment quality data are to be included in acknowledged and approved standards and recommendations to improve the credibility of the process and to solve the problem of quality assurance for wet welded joints. A comprehensive project., sponsored by the European Community under the Thermie Programme, is in progress to develop new testing procedures to generate the required data and design criteria for the future application of the wet welding process to main components of offshore structures. It is the sum of the project to establish additional fitness for purpose data for this process.
For years dry hyperbaric welding has achieved the highest credibility amongst offshore welding repair techniques, especially as the wet welding procedure could not achieve even a slightly comparable weldment quality. The credibility to this welding process was very poor because of the high porosity, high hardness and low ductility produced, but most of all because of the high hydrogen contamination with all the related negative influences. Nowadays the general trend in offshore repair techniques is to reduce repair and maintenance costs significantly. Dry Hyperbaric welding requires high investment and mobilization costs, expensive engineering activities, habitat fabrication and installation.
