Two-ton, Powdermet HIP'd valve body in super austenitic stainless steel.
Awareness is growing in the offshore industry of the benefits offered by high-grade steel components formed by the Hot Isostatic Processing method. This has led to demand for HIP specialist Powdermet's services running well above expectation this year, with orders from the Norwegian and Danish sectors.
The company will be supplying a large order of stainless steel for valves for Saga's Vigdis development. In the Danish sector it will supply a manifold for Maersk's Svend and Harald West projects in super duplex.
Late last year Powdermet received an urgent order for valve bodies for Conoco's Heidrun project. Thanks to the swiftness of the HIP process, these were delivered for machining and assembly in just six weeks.
Last year the company delivered a total of 20 valves, the largest weighing more than 3 tonnes, and other components in 6Mo austenitic and stainless steel for Norske Shell's Troll Gas terminal. Previously, it had supplied a 2.3t choke body - the largest ever built for offshore service - for the Troll Oil development. This was made from Avesta's 254SMO stainless steel grade.
Powdermet has worked closely with Avesta, now Avesta Sheffield, for around a decade. Now the two companies are offering flanges in a combination of 254SMO and 654SMO.
"The critical areas would be made from 654SMO and the remainder from 254SMO," says Carl-Gustav Hjorth, the components business area manager. "The part to be welded onto the pipeline would be in 254SMO, so standard welding procedures would be used. We believe this method of producing flanges will prove more economical than others."
Powdermet supplies the flanges to Avesta, which machines them. Avesta is also responsible for the marketing operation.
The advantage of the HIP process over conventionally forged or cast material is that it has a very fine and uniform grain structure, giving it the same mechanical properties in all directions. Manifolds with branches and pipes with flanges can be made in one piece, avoiding the need to weld on the branches or flanges to the main structures.
Hjorth accepts that materials like duplex and super duplex are expensive. On the other hand, he says, the weight is smaller compared with parts made in conventional grades; up to one third less welding is required; and the production process is rapid.
Powdermet is now owned 80% by Bodycoat International of the UK, which has a number of HIP facilities in Europe and the US. Previous owner ABB holds the remaining 20%.
For more information contact Carl-Gustav Hjorth, Powdermet: telephone +46 220 34800 or fax +46 220 33118.
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