STEEL PIPES FOR LOW TEMPERATURE HAVING HIGH STRENGTH AND METHOD FOR MANUFACTURING THE SAME

摘要

The present invention relates to low temperature steel which can be used in expanding a temperature from a low temperature to a room temperature of a liquefied gas storage tank, a transportation equipment, or the like; and the present invention provides low temperature steel having high strength, and a method to manufacture the same. The present invention comprises: 15-35 wt% of manganese (Mn); 23.6C+Mn>=28 and 33.5C-Mn<=23 wt% of carbon (C); less than or equal to 5 wt% of copper (Cu) (exclusive of 0 wt%); 28.5C+4.4Cr<=57 wt% of chromium (Cr) (exclusive of 0 wt%); 0.001-0.3 wt% of nitrogen (N); at least one of a group consisting of less than or equal to 0.1 wt% of titanium (Ti), less than or equal to 0.1 wt% of niobium (Nb), and less than or equal to 0.5 wt% of vanadium (V); and the remainder consisting of Fe and inevitable impurities.