Properties of High Toughness 9% Ni Heavy Section Steel Plate and Its Applocability to 200 000kl LNG storage Tanks

摘要

A 50mm thick 9% Ni steel plate containing Nband less Si has been manufactured for LNG storage tanks with acapacity of 200 000kl . Reduction of Si content and the additionof a Nb significantly improved HAZ toughness without a fall instrength .Furthermore ,the developed steel plate and its weldedjoints ,which were made of Ni-based weld materials exhibitedexcellent strength and toughness in actual tanks .Flawassessment proved that the developed steel plate and its weldedjoints have sufficient resistance to brittle fracture initiation andpropagation.