Offshore SAWL thick-wall large-diameter pipes for subsea gas pipelines (depths over 2500 m)
Offshore SAWL are thick-wall longitudinally welded large-diameter pipes for subsea gas pipelines at depths of over 2500 metres. The outside diameter is from 610 to 1524 mm, and a wall of up to 52 mm is achieved by multi-layer welding. Sections in the North Sea and the offshore lines of Nord Stream have been laid with these pipes.
- Type
- longitudinally welded SAWL (UOE) pipes for subsea laying
- Outside diameter
- 610 … 1524 mm; up to 48″ in projects
- Wall thickness
- up to 52 mm (multi-layer welding); Nord Stream 26.8…34.6 mm
- Depth
- over 2500 m
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
A pipeline on the seabed works in the harshest conditions, from Arctic temperatures to high pressures at depths of over 2500 metres. The strength and stable geometry of the pipe are decisive here, because uninterrupted gas supply depends on them even under extreme operating conditions.
The range for subsea laying is the same as for onshore, with an outside diameter from 610 to 1524 mm. For deep-water projects the manufacturer continuously develops the geometry and technological properties of the pipes. Multi-layer welding makes it possible to obtain a wall up to 52 mm thick, and extensive collapse resistance tests confirm quality. The pipes are made to API, EN and ISO standards and customer specifications, including DNV and NACE.
Offshore experience dates back to the 1970s. In the North Sea more than 6000 km of pipes with a total weight of more than 3 million t have been laid, for oil and gas, steel up to X70, including sour service versions, diameter up to 44 inches, wall up to 35 mm, design pressure up to 250 bar. For the four lines of Nord Stream and Nord Stream 2, among the longest offshore gas pipelines without intermediate compression, 1870 and 1100 km of 48-inch pipes with a wall of 26.8–34.6 mm made of SAWL 485 IFD steel were supplied. For the offshore section of the TAP gas pipeline, 36-inch pipes were supplied.
The pipes are made at the Mülheim an der Ruhr plant by the UOE process: edge crimping, forming in U- and O-presses, tack welding, internal and external seams by submerged arc welding, mechanical expansion, hydrostatic testing, sampling and destructive tests, final ultrasonic inspection of the weld, radiography (including film-free), acceptance and issue of certificates.
For offshore projects, buckle arrestors are also supplied, which are sections with a much greater wall thickness that prevent a buckle from propagating during laying, together with sacrificial anodes for electrochemical protection, which complements the passive action of the coatings. External and internal coatings are applied by a subsidiary. Loading reaches 600 pipes per day, about 40,000 t per vessel.
Technical specifications
| Type | longitudinally welded SAWL (UOE) pipes for subsea laying |
|---|---|
| Outside diameter | 610 … 1524 mm; up to 48″ in projects |
| Wall thickness | up to 52 mm (multi-layer welding); Nord Stream 26.8…34.6 mm |
| Depth | over 2500 m |
| Strength grades | up to X70, including sour gas; SAWL 485 IFD (DNV) |
| Design pressure | up to 250 bar |
| Standards | API 5L, DNV, EN, ISO, NACE (on request) |
| Additional | buckle arrestors (thickened buckle-limiting pipes), anodes |
| Coating | external (including weight coating) and internal, applied by a subsidiary |
Request a price and lead time
Offshore SAWL thick-wall large-diameter pipes for subsea gas pipelines (depths over 2500 m). We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
At what depths and in what conditions do these pipes work?
The pipes are intended for offshore gas pipelines at depths of over 2500 metres, from Arctic temperatures to high pressures. The design pressure in completed projects reached 250 bar.
What diameters and wall thicknesses were used in the Nord Stream projects?
For Nord Stream and Nord Stream 2, 48-inch pipes with a wall of 26.8–34.6 mm made of SAWL 485 IFD steel were supplied, 1870 and 1100 km respectively.
Are buckle arrestors supplied for offshore lines?
Yes, buckle arrestors are sections with a much greater wall thickness that prevent a buckle from propagating during laying. The wall of the main pipes reaches 52 mm, with a diameter from 610 to 1524 mm.
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