NEPTUNE Marine Services’ patented dry underwater welding technology has been qualified to 70msw (metres sea water) following a programme of research-and- development testing conducted at the UK’s National Hyperbaric Centre in Aberdeen.
Qualification of the NEPSYS technology to 70msw was achieved on two welds that were completed to specifications relating to both potential future client requirements and conventional applications.
The welds were independently witnessed and passed by Lloyds Register following a comprehensive programme of NDT and mechanical testing to the underwater welding code AWS D3.6M1999-Class A standard.
Another significant outcome of the 2009 R&D test programme for Neptune was the successful achievement of subsea “parent metal pre-heat” to 150C and post-weld dehydrogenation – processes that can be critical in achieving optimal metallurgy in certain materials.
Neptune is considering a return to the National Hyperbaric Centre next year to conduct R&D testing to depths towards and beyond 100msw (330ft sea water) and greater subsea parent metal pre-heat.
The company describes its patented NEPSYS dry underwater welding technology as a proven, class-approved alternative to conventional methods of offshore maintenance and repair that produces a permanent surface quality weld in an underwater environment and eliminates the need for drydocking or expensive hyperbaric repairs.
This is because the entire welding process is carried out in situ via portable, custom-designed welding habitats that are secured to the weld area to create a fully enclosed and controlled environment that isolates the weld zone from the surrounding environment.
Ideal welding conditions are thus created and maintained within the habitat via the continuous delivery of heated inert gas which prevents quenching and provides even thermal distribution.