While the industry´s established material, stainless steel, retains excellent qualities at cryogenic temperatures, it contracts by about 3 millimetres per metre in length when LNG flows through it.
For it to be used for straight-line service, this thermal movement has to be dealt with by introducing a mechanism such as a bellows at frequent intervals.
A highly promising alternative is Invar. This alloy of steel, containing 36% nickel, is well established in LNG cargo tanks where it is used as a membrane, typically around 3 millimetres thick.
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