Sheffield Forgemasters International Ltd (SFIL) has produced the largest ever forged sub-sea emergency repair clamp bodies for use on the world's longest sub-sea gas pipeline.
Sheffield Forgemasters has delivered two clamp bodies for Oil States each to form a crucial emergency repair back-up for the more than 1,200km Nord Stream pipeline which runs along the Baltic Sea floor from Vyborg (Russia) to Lubmin (Germany).
The hydro-clamp is designed to provide risk mitigation in the event of a breach in a sub-sea pipeline.
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Group projects director at Sheffield Forgemasters, George Brown explained: “The Nord Stream clamps are hydraulically operated repair mechanisms, designed to reinforce the Nord Stream Pipeline at any required point along the Baltic Sea floor.
“The size of the forging exceeded the known parameters for the designated material selection and required a new engineering solution to make it possible. Sheffield Forgemasters excels in these realms of manufacture where the practicable realisation of process capability is considered alongside the theoretical metallurgy.
Brown continued: “The clamp comprises of two matched halves which can be locked around the pipeline in order to stop any leakage.
“In order to provide the matched pairs of half clamps the forging was produced as a single piece before being cut longitudinally to produce the two halves. To achieve this, we worked close to the limits of capable production, starting with a 120 inch diameter ingot, a singular form for the whole clamp was forged, rough machined and heat treated.
“This provided a safe envelope for the finished shape which was then cut along its 22 foot length to produce two forgings which could be independently machined to the tight tolerances required before being finally reassembled and pressure tested.
Adding: “With a forged weight of over 200 tonnes, no sub-sea clamp of this size has ever been produced before and if required, can restore full structural and pressure integrity to the Nord Stream pipeline in the event of a leak or identified weakness.
“The unique capability we have at Sheffield Forgemasters, to go from creation of the material to completion of the finish machined pieces, was fundamental to the successful outcome of the clamp manufacture.”
