POSCO Holdings Inc.
CRYOGENIC AUSTENITIC HIGH-MANGANESE STEEL HAVING EXCELLENT CORROSION RESISTANCE, AND MANUFACTURING METHOD THEREFOR

Abstract:

The cryogenic austenitic high-manganese steel having excellent corrosion resistance, according to one aspect of the present invention, comprises 0.2-0.5 wt % of C, 23-28 wt % of Mn, 0.05-0.5 wt % of Si, 0.03 wt % or less of P, 0.005 wt % or less of S, 0.5 wt % or less of Al, and 3-4 wt % of Cr, with the remainder being Fe and other unavoidable impurities, also comprises at least 95 area % of austenite as a microstructure, and has Cr concentration sections continuously formed within an area of 50 .mu.m in the thickness direction from the surface, wherein the Cr concentration sections comprise a high Cr concentration section having a relatively high concentration of Cr, and a low Cr concentration section having a relatively low concentration of Cr, and the high Cr concentration section maybe distributed at 30 area % or less (but not 0%) relative to the whole surface area of the Cr sections.