OSC Marine Group is a recognized Subsea Engineering and Services company in underwater operations providing services for the Offshore and Coastal industry since 1962.

Hyperbaric Welding

There are two main zones where underwater welding is performed, namely the splash and underwater zone. The defects in the splash zone occur mainly due to collision and corrosion, in the underwater zone the defects are corrosion and high stresses in subsea members.  Where the weld must have a degree of pressure retaining integrity a Welding Habitat, Pressure resisting chamber or Cofferdam is used to ensure the integrity of weld. Wet welding is not performed due to hardness and brittleness resulting from the quenching effect of the surrounding water.

Wet Welding

Advantages – Low cost, High speed, Welder can reach parts of the offshore structure that couldn’t be welded by other methods, Readily available standard equipment.

Disadvantages – Quenching action of the water on the weld metal (decrease in metallurgical properties), Hydrogen embrittlement: H2 dissolved in the heat-affected zone (HAZ) and in the weld metal.

Dry Welding (Habitat)

Advantages – Welder safety is increased, Surface monitoring and better parts alignment due to good visibility, Non-destructive testing can be performed using conventional means.

Disadvantages – High pressure (in case of hyperbaric welding) and therefore its effects on gas solubility, Non-standard equipment is required.

OSC Marine Group is a recognized specialist in providing underwater
welding services since 1962.

Services include:

  • IMCA Air and Saturation Diving services
  • Wet and dry (habitat) underwater welding expertise
  • Development of welding procedures
  • WPS – wet/dry welding procedure specifications (example overleaf)
  • Diver qualification to approved WPS (AWS D3.6M for positions 2f, 3f, 4f, 3g and 6g)
  • Provision of wet/dry welding personnel (welders/supervisors)
  • Project management
  • NDT/NDE
  • QA/QC Management of projects
  • Dry space design

Specialized Diving Equipment

Specialist equipment and procedures are needed for offshore and remote areas, OSC has over the years enhanced its safety and capability in this area and offers a service that ensures Safe reliable underwater works.

All equipment is designed and built to meet IACS Design Codes or the IMCA Design guidelines.

OSC, since 2003, has been registered with IMCA for Air and Saturation Diving allowing the dive team to work to depths of 300m. Our decompression chambers are designed to provide immediate onsite decompression capabilities where needed.

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