POSCO Holdings Inc.
HIGH-STRENGTH AUSTENITE-BASED HIGH-MANGANESE STEEL MATERIAL AND MANUFACTURING METHOD FOR SAME

Abstract:

A high-strength austenite-based high-manganese steel material and a manufacturing method for the same, the steel material comprising: manganese (Mn): 20 to 23 wt %, carbon (C): 0.3 to 0.5 wt %, silicon (Si): 0.05 to 0.50 wt %, phosphorus (P): 0.03 wt % or less, sulfur (S): 0.005 wt % or less, aluminum (Al): 0.050 wt % or less, chromium (Cr): 2.5 wt % or less, boron (B): 0.0005 to 0.01 wt %, nitrogen (N): 0.03 wt % or less, and a balance of iron (Fe) and other inevitable impurities, wherein stacked defect energy (SFE) represented by the following relationship 1 is 3.05 mJ/m.sup.2 or more, and a microstructure comprises 95 area % or more (including 100 area %) of austenite, and comprises 6 area % or more of strain grain boundaries in an austenite recrystallized grain, is provided. SFE (mJ/m.sup.2)=-24.2+0.950*Mn+39.0*C-2.53*Si-5.50*Al-0.765*Cr [Relationship 1] where Mn, C, Cr, Si, and Al denote weight percent of respective components.