WET WELDING "COMES OF AGE"
Hydroweld and Underwater Technical Services pooled their technical and administrative skills to successfully complete a contract for DML (Devonport Management Ltd), the newly privatised company operating in Devonport dockyard, who carry out work on behalf of the MoD (Ministry of Defence). The project, the first ever of its kind, required the wet welding of over 40 blanking plates to the ballast tanks of a submarine, the largest being 2.6 x 1.2 metres. The contract was completed on time, in budget with no lost time accidents and at a fraction of the cost of dry docking. All of the wet welding was completed using Hydroweld FS™ wet welding electrodes, which are the only underwater welding electrodes have been approved, by the MoD, for permanent and temporary repairs to war ships. This project further proved the electrodes capabilities and welding techniques used by Hydroweld, through the successfully completion of wet welding procedures and production welding on materials with a relatively high carbon equivalent, up to 0.47% . The accepted normal upper limit is 0.40% using ferritic electrodes. The welding was carried out by a selected team of 20 coded wet welder divers, who’s variety of skills and commitment to the project was invaluable and who must be commended. All of the wet welds were subjected to 100% visual inspection and MPI by the client with a 100% pass rate. The welding procedures and welder qualification testing was completed in three positions, Horizontal, Vertical and Overhead, in 8 metres of water at Hydroweld’s underwater welding facilities at Stoney Cove in Leicestershire. The coupons were welded and tested an accordance with the ANSI/AWS D3.6 – 93 Specification for Underwater Welding and were witnessed by Lloyds Registers of Shipping and DML. All of the welding was monitored via hat mounted CCTV. "The projects success has generated a lot of interest both here in the UK and overseas" said Michael Pett from Hydroweld, "yet again we are breaking new ground and pushing back technological boundaries". This projects was monitored very closely, by the MoD and DML, with every step being subjected to an unparalleled and rigorous set of quality control measures which were implemented to the letter. In a recent presentation given in the presence of some leading officials involved with underwater engineering from the MoD and other overseas naval guests, Barry Richards (welding and NDT manager for DML) declared that wet welding has at last "come of age" Mr Richards who was responsible for ensuring the wet welding was completed to specification said "If I hadn’t seen it for myself I would never have believed that such high quality welding could be achieved in underwater. A lot of samples taken from coupons produced during the welding procedures, are almost impossible to distinguish from welds completed in the dry and their mechanical properties more than meet the specification".
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