STEEL MATERIAL, PROCESS FOR PRODUCING SAME, AND LNG TANK

摘要

A steel is provided in which a lower limit of an amount of retained ³ at a (1/4)t location regarding a plate thickness t of the steel is 4.0 volume%, the retained ³ has a form in which an upper limit of an average of an aspect ratio thereof is 2.5 and an upper limit of an average of a major axis thereof is 0.85 µm, and an average Mn concentration in the retained ³ and an average Ni concentration in the retained ³ satisfy relationships of[Mn] retained ³ > [Mn] ± ×1.4, and [Ni] retained ³ > [Ni] ± ×1.4.