Cryogenic materials for marine service
The steels, alloys and insulation used at LNG temperature aboard ship, the ductile to brittle transition that rules ordinary hull steel out, and the qualification tests.
Cryogenic materials for marine service are the metals, alloys and insulation systems qualified to remain ductile and dimensionally stable at liquefied gas temperature. The governing failure mode is not corrosion or wear but brittle fracture, because ordinary hull steel loses its ductility well above the temperature at which LNG is carried.
That single property decides the material list. Austenitic stainless steels, nickel steels and certain aluminium alloys retain useful toughness far below the transition temperature of shipbuilding grades, and everything in contact with the liquid, or credibly exposed to a spill of it, is drawn from that list. The structure beneath is protected by containment, drip trays and spill deflection rather than by material choice.
The full article will cover the transition temperature and the impact testing that establishes it, the qualified material grades and their service limits, weld procedure qualification at temperature, insulation systems, and the cold spill protection of the deck and hull structure. See LNG fuel system .