Weld Repair of Shell Plates During Seagoing Operations
2002 (English)In: Proceedings of OMAE02; 21st International Conference on Offshore Mechanics and Artic Engineering: June 23-28, 2002, Oslo, Norway, ASME Press, 2002, Vol. 3, 499-506 p.Conference paper (Refereed)
An algorithm to estimate the cooling rate of welding seamson the shell plating of a ship, below the waterline, while it is onvoyage has been derived. The demand for this technique hasarisen from the wish of ship operators to make it possible forthe safe repair of ship structures without taking them out ofoperation.  The strength of the shell plating after welding isdetermined by its metallurgic structure, which is dependent onthe cooling rate, its chemical composition and the original grainsize of the base material.  The cooling rate for this type ofwelding seam depends on the velocity of the water flow, thedistance from the bow, the thickness of the plate, and the heatfrom the heat input of the welding. The algorithm makes itpossible to calculate the cooling rate for a base material affectedby a forced flow of fluid by means of Rosenthals equation andthus enabling suitable welding parameters to be determined.As the welding parameters can be chosen to fit the specificrepair to be made, it is now possible to determine the suitabilityof a welding procedure in advance. The algorithm is applicablewhen determining welding parameters at Hot-Tappingoperations as well, where the base material is affected by aforced flow of fluid. A number of experiments have beenperformed and the results support the theoretical model. Theresearch project continues with the aim of finding an algorithmto include the enhanced cooling rate due to the layer of boilingfluid on the back of the base material. A method to improve themeasurements of the most important parameter in the algorithmhas been developed and makes it possible to build up aquantitative database of typical values for various configurations.
Place, publisher, year, edition, pages
ASME Press, 2002. Vol. 3, 499-506 p.
welding, in-service, heat transfer, seagoing operation, forced flow of fluid, boundary layer
Vehicle Engineering Manufacturing, Surface and Joining Technology
Research subject Shipping, Maritime Science
IdentifiersURN: urn:nbn:se:lnu:diva-61991DOI: 10.1115/OMAE2002-28583ISBN: 0-7918-3613-4 (print)ISBN: 0-7918-3599-5 (electronic)OAI: oai:DiVA.org:lnu-61991DiVA: diva2:1085905
ASME 21st International Conference on Offshore Mechanics and Artic Engineering, June 23-28, 2002, Oslo, Norway