Steel for low-temperature service having excellent surface processing quality and method for manufacturing same

Abstract

Provided is a steel sheet for low-temperature service, which can be used at a wide temperature range from low temperature to room temperature in liquefied gas storage tanks and transport facilities. The steel sheet for low-temperature service has an excellent surface processing quality even after a processing processes is performed, such as a tension process. The a steel sheet contains manganese (Mn, 15-35 wt %), carbon (C, satisfying 23.6C+Mn≧28 and 33.5C—Mn≦23), copper (Cu, 5 wt % or less (excluding 0 wt %)), chrome (Cr, satisfying 28.5C+4.4Cr≦57 (excluding 0 wt %)), titanium (Ti, 0.01-0.5 wt %), nitrogen (N, 0.003-0.2 wt %), the balance iron (Fe), and other inevitable impurities. Ti and N satisfy relational expression 1 below. [Relational expression 1] 1.0≦Ti/N≦4.5 (Mn, C, Cr, Ti, and N in the respective expressions mean wt % of respective ingredient contents).

Dependencies are inferred from the claim text.