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Improving Global Quality of Life
Through Optimum Use and Innovation of Welding and Joining Technologies
9.3.2
Hot Topics
The following issues and technical areas are considered to be the key topics for future technical developments
of welding, joining and allied technologies:
Deepwater exploration and production
Whole-life performance of steel risers.
New materials for risers, both ferrous and non-ferrous.
Inspection of risers.
Dissimilar materials joint performance.
Pipeline wall thickness, laying and welding.
Materials challenges for exploration in arctic region and transportation of fuels
High-productivity welding of pipelines.
Manufacturing technologies for tankers and gas carriers.
On-line repair techniques of pipelines.
New design concepts for high-productivity pipe-lay.
Advanced inspection techniques of transportation structures (pipelines; liquid natural gas carriers
and tankers).
Corrosion mitigation technique developments (coatings etc).
Life extension of ageing assets.
Training, qualification and certification of joining and allied human resources in emerging markets.
9.3.3
Hyperbaric welding
Hyperbaric welding is the process of welding at elevated pressures, normally underwater. It can either take
place
wet
in the water itself or
dry
inside a specially constructed positive pressure enclosure and hence a dry
environment. It is predominantly referred to as“hyperbaric welding” when used in a dry environment, and
«
underwater welding» when in a wet environment. The applications of hyperbaric welding are diverse – it is
often used to repair ships, offshore oil platforms, and pipelines. Steel is the most common material welded.
The demand for highly sophisticated underwater procedures and technologies is increasing, driven by deep
sea oil and gas development and by marine infrastructure development and repair around the world.
Dry hyperbaric welding is used in preference to wet underwater welding when high quality welds are
required because of the increased control over conditions which can be exerted, such as through application
of prior and post weld heat treatments. This improved environmental control leads directly to improved
process performance and a generally much higher quality weld than a comparative wet weld. Thus, when
a very high quality weld is required, dry hyperbaric welding is normally utilised. Research into using dry
hyperbaric welding at depths of up to 1,000 metres (3,300 ft) is ongoing. In general, assuring the integrity
of underwater welds can be difficult (but is possible using various nondestructive testing applications),
especially for wet underwater welds, because defects are difficult to detect if the defects are beneath the
surface of the weld.
The majority of work performed by an average welder-diver does not involve the welding operation itself,
but rather executing the tasks that lead up to and follow the actual welding activities. Except under special
circumstances, a welder-diver in most cases must possess both certified welder skills and commercial diving skills.
