PRESSURE VESSEL STEEL WITH EXCELLENT SULFIDE STRESS CRACKING RESISTANCE AND LOW TEMPERATURE TOUGHNESS AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A steel material for a pressure container with the excellent sulfide stress cracking resistance and low temperature toughness and a manufacturing thereof are provided to have the excellent stress cracking resistance in a condition of H2S and the excellent impact toughness at the low temperature in which the ductility-transition temperature is 10°C or less. CONSTITUTION: A steel material for a pressure container with excellent sulfide stress cracking resistance and low temperature toughness is composed of, in wt%: C: 0.03-0.18; Si: 0.05-0.5; Mn: 0.5-2.0; Al: 0.005-0.1; Cu: 0.15-0.5; Ni: 0.15-1.0; Nb: 0.01-0.05; Ti: 0.01-0.05; Ca: 0.001-0.003; N: 0.001-0.01; P: 0.012% or less; S: 0.0015% or less; C/Mn: 0.04-0.16 and ( (Nb+Ti+V)*0.1) / (C*0.01+N): 0.4-1.6; and the remainder Fe and other inevitable impurities. The steel material additionally includes at least one kind among Mo, Cr, W, and V.