Austenitic light weight steel

Abstract

Disclosed is an austenitic light weight steel which may have decreased specific gravity while maintaining excellent strength and ductility. The austenitic light weight steel may include carbon (C) in an amount of about 0.8 to 1.3 weight %, aluminum (Al) in an amount of about 9.0 to 15.0 weight %, manganese (Mn) in an amount of about 10.0 to 20.0 weight %, nickel (Ni) in an amount of about 0.25 weight % or less (excluding 0 weight %), chromium (Cr) in an amount of about 0.5 weight % or less (excluding 0 weight %), silicon (Si) in an amount of about 0.5 weight % or less (excluding 0 weight %), a sum of titanium (Ti) and vanadium (V) in an amount of about 1.0 weight % or less (excluding 0 weight %), other unavoidable impurities, and iron (Fe) constituting the remaining balance, based on the total weight of the light weight steel.

What is claimed is: 
     
         1 . An austenitic light weight steel comprising:
 carbon (C) in an amount of about 0.8 to 1.3 weight %,   aluminum (Al) in an amount of about 9.0 to 15.0 weight %,   manganese (Mn) in an amount of about 10.0 to 20.0 weight %,   nickel (Ni) in an amount of about 0.25 weight % or less (excluding 0 weight %),   chromium (Cr) in an amount of about 0.5 weight % or less (excluding 0 weight %),   silicon (Si) in an amount of about 0.5 weight % or less (excluding 0 weight %),   a sum of titanium (Ti) and vanadium (V) in an amount of about 1.0 weight % or less (excluding 0 weight %),   other unavoidable impurities, and   iron (Fe) constituting the remaining balance,   all the weight % based on the total weight of the light weight steel.   
     
     
         2 . The austenitic light weight steel of  claim 1 , further comprising:
 niobium (Nb) in an amount of about 0.03 weight % or less,   phosphorus (P) in an amount of about 0.1 weight % or less,   sulfur (S) in an amount of about 0.05 weight % or less,   nitrogen (N) in an amount of about 0.01 weight % or less,   or a combination thereof,   based on the total weight of the light weight steel.   
     
     
         3 . The austenitic light weight steel of  claim 1 , wherein the austenitic light weight steel has a yield strength of about 600 MPa or greater. 
     
     
         4 . The austenitic light weight steel of  claim 1 , wherein the austenitic light weight steel has a tensile strength of about 1000 MPa or greater. 
     
     
         5 . The austenitic light weight steel of  claim 1 , wherein the austenitic light weight steel has an elongation of about 20% or greater. 
     
     
         6 . The austenitic light weight steel of  claim 1 , wherein the austenitic light weight steel has a density of about 6.85 g/cm 3  or less. 
     
     
         7 . The austenitic light weight steel of  claim 1 , wherein in the austenitic light weight steel, a matrix is an austenite, and a ferrite is formed at a fraction of about 15% or less. 
     
     
         8 . The austenitic light weight steel of  claim 7 , wherein in the austenitic light weight steel, a κ-carbide is formed at a fraction of about 10% or less. 
     
     
         9 . The austenitic light weight steel of  claim 7 , wherein in the austenitic light weight steel, a Fe—Al intermetallic compound is formed at a fraction of about 2% or less. 
     
     
         10 . The austenitic light weight steel of  claim 1 , wherein a grain of the austenitic light weight steel is formed to have a length of about 40 μm or less in a rolling direction. 
     
     
         11 . The austenitic light weight steel of  claim 1 , wherein in the austenitic light weight steel, β-Mn is not formed. 
     
     
         12 . The austenitic light weight steel of  claim 1 , consisting essentially of:
 carbon (C) in an amount of about 0.8 to 1.3 weight %,   aluminum (Al) in an amount of about 9.0 to 15.0 weight %,   manganese (Mn) in an amount of about 10.0 to 20.0 weight %,   nickel (Ni) in an amount of about 0.25 weight % or less (excluding 0 weight %),   chromium (Cr) in an amount of about 0.5 weight % or less (excluding 0 weight %),   silicon (Si) in an amount of about 0.5 weight % or less (excluding 0 weight %),   a sum of titanium (Ti) and vanadium (V) in an amount of about 1.0 weight % or less (excluding 0 weight %),   other unavoidable impurities, and   iron (Fe) constituting the remaining balance,   all the weight % based on the total weight of the light weight steel.   
     
     
         13 . The austenitic light weight steel of  claim 1 , consisting essentially of:
 carbon (C) in an amount of about 0.8 to 1.3 weight %,   aluminum (Al) in an amount of about 9.0 to 15.0 weight %,   manganese (Mn) in an amount of about 10.0 to 20.0 weight %,   nickel (Ni) in an amount of about 0.25 weight % or less (excluding 0 weight %),   chromium (Cr) in an amount of about 0.5 weight % or less (excluding 0 weight %),   silicon (Si) in an amount of about 0.5 weight % or less (excluding 0 weight %),   a sum of titanium (Ti) and vanadium (V) in an amount of about 1.0 weight % or less (excluding 0 weight %),   one or more selected from the group consisting of niobium (Nb) in an amount of about 0.03 weight % or less, phosphorus (P) in an amount of about 0.1 weight % or less, sulfur (S) in an amount of about 0.05 weight % or less, nitrogen (N) in an amount of about 0.01 weight % or less,   other unavoidable impurities, and   iron (Fe) constituting the remaining balance,   all the weight % based on the total weight of the light weight steel.   
     
     
         14 . A vehicle part comprising an austenitic light weight steel of  claim 1 . 
     
     
         15 . A vehicle comprising an austenitic light weight steel of  claim 1 .