-- A Mn-Mo-Ni BASED STEEL FOR PRESSURE VESSEL HAVING SUPERIOR TOUGHNESS

摘要

PURPOSE: A steel for a pressure vessel is provided which increases toughness strength by adding a trace of B and Ti to a Mn-Mo-Ni based steel so that carbide and nitride are finely deposited, and improves toughness by solid dissolving B into a matrix. CONSTITUTION: The Mn-Mo-Ni based steel for a pressure vessel having superior toughness comprises 0.10 to 0.14 wt.% of C; 0.1 to 0.4 wt.% of Si; 1.0 to 1.5 wt.% of Mn; 0.4 to 0.6 wt.% of Mo; 0.4 to 0.7 wt.% of Ni; 0.0005 to 0.003 wt.% of B; 0.005 to 0.02 wt.% of Ti; 0.01 to 0.03 wt.% Al; 0.010 wt.% or less of P; 0.003 wt.% or less of S; 0.005 wt.% or less of N; and a balance of Fe and other inevitable impurities.