Offshore - Exxon Company, U.S.A. | Harmony Construction
ORBITAL WELDING ON COPPER-NICKEL PIPE USED ON FIREWATER SYSTEM
A welding head is shown installed on the copper-nickel pipe.
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Model 15

Replacement of the firewater system on Exxon's Hondo offshore platform required fabrication of a piping system utilizing the latest concepts in material selection, metal fabrication, and joining technology. The system distributes seawater supplying deluge spray nozzles at various points on the platform and consists of a manifold system of 10-in. pipe with a wall thickness of 0.187-in.

The system required 9,000 ft. of pipe of all sizes up to 10 in. and needed 3,140 welds. All welds were to conform to ANSI B31.3. It was very important to get a good mixture of the filler wire, which was Monel 67, into the root pass in order to achieve an acceptable weld. Orbital welding was evaluated, and subsequently chosen, as an alternate joining method to manual welding.

The use of AMI's orbital pipe welding equipment on copper-nickel pipe dramatically reduced the reject rate compared to manual welding. The quality was obtained on the first pass, and the welds no longer had to be cut apart and rewelded.

Reprinted from Offshore/Oilmen


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