STEEL MATERIAL, PROCESS FOR PRODUCING SAME, AND LNG TANK

摘要

This steel material has a content of retained γ, measured at a position corresponding to 1/4 the plate thickness t of the steel material, of at least 4.0 vol%. The retained γ has such a shape that the average aspect ratio is at most 2.5 and the average major-axis length is at most 0.85 μm, and the average Mn concentration and average Ni concentration in the retained γ satisfy [Mn]retained γ>[Mn]α×1.4 and [Ni]retained γ>[Ni]α×1.4, respectively.