Austenite steel material having superior ductility

Abstract

Provided is an austenite steel having excellent ductility including 8 wt % to 15 wt % of manganese (Mn), 3 wt % or less (excluding 0 wt %) of copper (Cu), a content of carbon (C) satisfying relationships of 33.5C+Mn≧25 and 33.5C−Mn≦23, and iron (Fe) as well as unavoidable impurities as a remainder. According to an aspect, austenite is stabilized and generation of carbides in a network form at austenite grain boundaries is inhibited by adding copper (Cu) favorable to inhibition of carbide formation with respect to manganese and appropriately controlling contents of carbon and manganese, and thus, high economic efficiency may also be achieved while ductility and wear resistance are improved.

1 . An austenite steel having excellent ductility comprising:
 8 wt % to 15 wt % of manganese (Mn);   3 wt % or less (excluding 0 wt %) of copper (Cu);   a content of carbon (C) satisfying relationships of 33.5C+Mn≧25 and 33.5C−Mn≦23; and   iron (Fe) as well as unavoidable impurities as a remainder.   
     
     
         2 . The austenite steel having excellent ductility of  claim 1 , wherein the steel further comprises 8 wt % or less (excluding 0 wt %) of chromium (Cr). 
     
     
         3 . The austenite steel having excellent ductility of  claim 1 , wherein the steel further comprises 0.05 wt % or less (excluding 0 wt %) of titanium (Ti) and 0.1 wt % or less (excluding 0 wt %) of niobium (Nb). 
     
     
         4 . The austenite steel having excellent ductility of  claim 3 , wherein yield strength of the steel is 500 MPa or more. 
     
     
         5 . The austenite steel having excellent ductility of  claim 3 , wherein the steel further comprises 0.002 wt % to 0.2 wt % of nitrogen (N). 
     
     
         6 . The austenite steel having excellent ductility of  claim 1 , wherein a microstructure of the steel comprises austenite having an area fraction of 95% or more. 
     
     
         7 . The austenite steel having excellent ductility of  claim 6 , wherein magnetic permeability of the steel is 1.01 or less at a tensile strain of 20%. 
     
     
         8 . The austenite steel having excellent ductility of  claim 2 , wherein a microstructure of the steel comprises austenite having an area fraction of 95% or more.