High mangese steel for low temperature applications having excellent surface quality and a manufacturing method thereof

A method of manufacturing a high manganese steel for low temperature applications, the method comprising:

• preparing a slab comprising 0.3 wt % to 0.8 wt % of C, 18 wt % to 26 wt % of Mn, 0.01 wt % to 1 wt % of Si, 0.01 wt % to 0.5 wt % of Al, 0.1 wt % or less of Ti (excluding 0%), 1 wt % to 4.5 wt % of Cr, 0.1 wt % to 0.9 wt % of Cu, 0.03 wt % or less of S (excluding 0%), 0.3 wt % or less of P (excluding 0%), 0.001 wt % to 0.03 wt % of N, 0.004 wt % or less of B (excluding 0%), and a remainder of Fe and other inevitable impurities;
• deformation application involving applying a deformation to the slab such that a recrystallization microstructure is formed on a surface layer portion of the slab;
• air cooling involving air-cooling the slab on which the recrystallization microstructure is formed on the surface layer portion thereof to room temperature;
• reheating involving heating the air-cooled slab to 1100° C. to 1250° C.;
• hot rolling involving finish-rolling the reheated slab at 850° C. to 950° C. to obtain a hot-rolled steel;
• and
• accelerated cooling involving accelerated-cooling the hot-rolled steel at a cooling speed of 10° C./sec or more to a accelerated cooling termination temperature of 600° C. or less.