STEEL PLATE FOR PRESSURE VESSEL WITH HIGH SOHIC RESISTANCE

摘要

A steel plate for pressure vessel with high SOHIC(Stress Oriented Hydrogen Induced Cracking) resistance is provided to remove the need of normalizing thermal process by controlling the fraction of micro-structure consisting of ferrite and bainite through recrystallization controlled rolling and accelerated freezing. A steel plate for pressure vessel with high SOHIC resistance contains C: 0.10~0.30wt%, Si: 0.15~0.40wt%, Mn: 0.6~1.2wt%, Al: 0.001~0.05wt%, P: 0.035wt% or below, S: 0.020wt% or below, and Ca: 5~50ppm. The steel plate also includes one or more than two kinds selected from the group consisting of Cr: 0.35wt% or below, Mo: 0.2wt% and below, Ni: 0.5wt% or below, V: 0.05wt% and below, and Nb: 0.05wt% or below. The micro-structure of the steel plate is two-phase composite structure.