Underwater Welding: Qualification & Requisites

Underwater welding is a fantastic low cost and effective NDT technique, but performing it requires welders to know about certain things.

In case of any underwater welding operation, the required test welds are created under either simulated or actual conditions for the necessary application. Before the qualification testing begins, the welding company that undertakes the operation has to make sure that every operator and welder involved in it possesses sufficient understanding of the following essentials:

• Importance of the various welding parameters
• Elementary welding techniques that are to be used
• Functions of the different pieces of equipment
• Response of the relevant materials
• Pertinent regulations and specifications of the welding inspection to be conducted
• Relevant non-destructive testing methods
• Suitable acceptance criteria for the weld defects
  Handling of od welding consumables

Besides having a sound idea of the things mentioned above, it is also important for the involved personnel to have effectively passed a suitable welding assessment above water prior to being permitted for underwater welding. Also before conduction of the tests, the professionals who would be taking care of the operation are provided with adequate training so that they become familiar with influences of atmosphere, temperature, pressure and other factors.

The applicability of the pertinent welder’s certificate is provided as per the relevant welding positions. At significant water depths, diving modes or other pressure, the applicability is decided in every case. Any alteration of coated electrodes generally necessitates requalification for the underwater welders.

By chance the welding gets interrupted for more than a time period of 3 months, underwater welders involved in the operation will have to get their certificates renewed. The retest done after that comprises making of at least one test coupon (which is roughly 300 to 400mm in length) in an accepted welding position. The coupon is then examined visually and thereafter, using radiographic testing. It must be noted that the performance test would be done as per specifications of the initial qualification in case the interrupted period goes beyond 6 months.

In general, for those underwater welders who stay on standby without being associated with welding operations regularly, the conditions dictating maintenance of qualification are agreed upon specially.

Underwater welding is highly beneficial because it ensures quality weld, driver safety, surface monitoring, minimal usage of equipment and high operating speed. Besides that, it is also quite affordable and very versatile. That is why, it is used for a large number of applications in Melbourne, including oil refineries, tunnels, pipelines, construction, offshore, submarines and ships. In future, the method is even expected to help invent similar new techniques.