STEEL HAVING EXCELLENT LOW TEMPERATURE TOUGHNESS AND HYDROGEN INDUCED CRACKING RESISTANCE AND MANUFACTURING METHOD THEREOF

摘要

The present invention relates to a steel material with excellent low temperature toughness and hydrogen induced cracking resistance comprising: 0.03-0.05 wt% of carbon (C); 0.05-1.0 wt% of silicon (Si); 1.0-1.4 wt% of manganese (Mn); 0.010 wt% or less of phosphorus (P); 0.0020 wt% or less of sulfur (S); 0.005-0.1 wt% of aluminum (Al); 0.1-0.3 wt% of copper (Cu), 0.1-0.5 wt% of nickel (Ni); 0.05-0.3 wt% of chrome (Cr); 0.02-0.3 wt% of molybdenum (Mo); 0.03-0.055 wt% of niobium (Nb); 0.01-0.02 wt% of titanium (Ti); 0.02-0.06 wt% of vanadium (V); 0.0005-0.003 wt% of calcium (Ca); 0.001-0.01 wt% of nitrogen (N); and the remainder consisting of iron (Fe) and inevitable impurities, and to a manufacturing method thereof. The purpose of the present invention is to provide the steel material with excellent low temperature toughness and hydrogen induced cracking resistance, and the manufacturing method thereof.