Centrifugally cast bimetallic pipe for offshore corrosion resistant pipelines
- Kubota Corp., Hirakata (Japan)
Centrifugally cast bimetallic pipes and fittings have been developed for the use of offshore oil and gas production. The metallurgical properties, mechanical properties, and corrosion properties of centrifugal a cast bimetallic pipe with outside metal of API 5L X52 to X65 internally clad with alloy 825 and 625 are discussed. First, molten steel for outer pipe is introduced into a rotating metallic mold. During the solidification of the outer pipe (carbon steel), the temperature of the pipe inside is monitored. After the solidification of the outer pipe, and when a certain temperature is reached, then a corrosion resistant alloy such as Alloy 825 or 625 for inside layer is poured. By controlling the casting conditions and selecting suitable flux, sound metallurgical bonded bimetallic pipe is produced with a minimum mixing layer at the interface also keeping a homogeneous outside wall thickness along the pipe length. The weld joints of the pipe are also evaluated from the view points of weldability, mechanical strength, fracture toughness, and corrosion resistance properties. The welding method applied was basically TIG welding (GTAW). COD tests at {minus}10 C are applied to the welds to investigate fracture toughness of the weld joints. Huey test according to ASTM A262C is carried out on the root of the welds as the corrosion test. As a result, the weld joint using filler wire of alloy625 from root to cover pass has proved a very reliable method from the point of view of mechanical and corrosion resistance properties. These centrifugally cast bimetallic pipes and fittings have been widely used for riser pipes, template process lines, top side and subsea manifolds, and flow bends for christmas trees in the North Sea.
- OSTI ID:
- 398019
- Report Number(s):
- CONF-940409-; ISBN 1-880653-10-9; TRN: IM9649%%227
- Resource Relation:
- Conference: 4. international conference on offshore and polar engineering, Osaka (Japan), 10-15 Apr 1994; Other Information: PBD: 1994; Related Information: Is Part Of The proceedings of the fourth (1994) international offshore and polar engineering conference. Volume 2; Chung, J.S. [ed.] [Colorado School of Mines, Golden, CO (United States)]; Karal, K. [ed.] [Norwegian Contractors, Stabekk (Norway)]; Koteryama, Wataru [ed.] [Kyushu Univ., Kasuga (Japan)]; PB: 640 p.
- Country of Publication:
- United States
- Language:
- English
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