Underwater welding

Ever more significance is being attached to underwater welding due to the increasing utilisation of offshore wind farms. Underwater welding is used for the construction and maintenance of docks, waterways, underwater pipelines, lock installations, dams, hydroelectric power stations and offshore platforms, for shipbuilding as well as for salvaging measures. At present, the public is following the complicated salvaging of the Costa Concordia cruise ship off the Italian island of Giglio. This is only possible due to one of the largest deployments of welding divers in history.

In the case of underwater welding, a distinction is made between two processes: In the dry process, the area around the welding work is drained with the aid of compressed air using special diving chambers or bells. In wet welding, an underwater welder in diver's equipment carries out the welding work in the water.

Arc welding with an electrode and direct current is frequently utilised for wet welding. Due to the arc, the water evaporates at the welding point and the heat makes the material melt. One particular challenge in order to achieve an adequate weld quality is the high hydrogen content in the gas bubble during the welding process.

Not only manual metal arc welding but also the MIG/MAG, TIG and MF processes are utilised. Laser welding processes are being developed or tried out.

According to Chapter 5.3 of the DVS 1801 technical code, GSI is a recognised body for the certification of manufacturers which carry out wet underwater welding work.

GSI trains underwater welders according to the DVS 1186 guideline. The prerequisite for taking part in the course is the final qualification as a "certified diver".

GSI provides you with support and advice with regard to all questions for everything to do with the subjects of materials, joining processes, testing procedures, corrosion protection as well as personnel qualification and training.

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