High manganese nitrogen-containing steel sheet having high strength and high ductility, and method for manufacturing the same

Abstract

Provided is a high manganese nitrogen-containing steel sheet. The high manganese nitrogen-containing steel sheet according to the present invention comprises 0.5 to 1.0 wt % of carbon, 10 to 20 wt % of manganese, 0.02 to 0.3 wt % of nitrogen, with a remainder of Fe and unavoidable impurities. The high manganese nitrogen-containing steel sheet according to the present invention produces an austenite phase at room temperature, in which the stacking fault energy is effectively controlled by adding chrome and nitrogen. Accordingly, the high manganese nitrogen-containing steel sheet of the present invention produces a mechanical twin during the plastic deformation of the steel sheet, thereby increasing the work hardening rate, tensile strength, and workability.

1 . A high manganese-nitrogen containing steel sheet comprising:
 0.5 to 1.0 wt % of carbon;   10 to 20 wt % of manganese;   0.02 to 0.2 wt % of nitrogen; and   the balance of Fe and unavoidable impurities.   
     
     
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         20 . The high manganese-nitrogen containing steel sheet of  claim 1 , wherein at least part of the nitrogen is contained in the steel sheet through arc-melting. 
     
     
         21 . The high manganese-nitrogen containing steel sheet of  claim 1 , wherein the steel sheet has a product of tensile strength to total elongation (TS×El) of 50,000 MPa % or more. 
     
     
         22 . The high manganese-nitrogen containing steel sheet of  claim 1 , wherein manganese is present in an amount of 15 to 18 wt %. 
     
     
         23 . The high manganese-nitrogen containing steel sheet of  claim 1 , wherein nitrogen is present in an amount of 0.10 to 0.2 wt %. 
     
     
         24 . A high manganese-nitrogen containing steel sheet comprising:
 0.5 to 1.0 wt % of carbon;   10 to 20 wt % of manganese;   4.0 wt % or less of chrome;   0.02 to 0.3 wt % of nitrogen; and   the balance of Fe and unavoidable impurities.   
     
     
         25 . The high manganese-nitrogen containing steel sheet of  claim 24 , wherein at least part of the nitrogen is contained in the steel sheet through arc-melting. 
     
     
         26 . The high manganese-nitrogen containing steel sheet of  claim 24 , wherein the steel sheet has a product of tensile strength to total elongation (TS×El) of 50,000 MPa % or more. 
     
     
         27 . The high manganese-nitrogen containing steel sheet of  claim 24 , wherein manganese is present in an amount of 15 to 18 wt %. 
     
     
         28 . The high manganese-nitrogen containing steel sheet of  claim 24 , wherein nitrogen is present in an amount of 0.10 to 0.3 wt %. 
     
     
         29 . A high manganese-nitrogen containing steel sheet comprising:
 0.5 to 1.0 wt % of carbon;   10 to 20 wt % of manganese;   4.0 wt % or less of chrome;   0.02 to 0.3 wt % of nitrogen;   at least one of less than 4 wt % of silicon, less than 3 wt % of aluminum, less than 0.30 wt % of niobium, less than 0.30 wt % of titanium and less than 0.30 wt % of vanadium; and   the balance of Fe and unavoidable impurities.   
     
     
         30 . The high manganese-nitrogen containing steel sheet of  claim 29 , wherein at least part of the nitrogen is contained in the steel sheet through arc-melting. 
     
     
         31 . The high manganese-nitrogen containing steel sheet of  claim 29 , wherein the steel sheet has a product of tensile strength to total elongation (TS×El) of 50,000 MPa % or more. 
     
     
         32 . The high manganese-nitrogen containing steel sheet of  claim 29 , wherein manganese is present in an amount of 15 to 18 wt %. 
     
     
         33 . The high manganese-nitrogen containing steel sheet of  claim 29 , wherein nitrogen is present in an amount of 0.10 to 0.3 wt %. 
     
     
         34 . A method of manufacturing a high manganese-nitrogen containing steel sheet, comprising:
 placing electrolytic iron, electrolytic manganese and carbon powder in a chamber;   filling the chamber with an argon-nitrogen atmosphere; and   arc-melting the electrolytic iron, electrolytic manganese and carbon powder,   wherein the manufactured steel sheet comprises:
 0.5 to 1.0 wt % of carbon, 
 10 to 20 wt % of manganese, 
 0.02 to 0.2 wt % of nitrogen, and 
 the balance of Fe and unavoidable impurities. 
   
     
     
         35 . The method of  claim 34 , wherein the arc-melting is repeated plural times. 
     
     
         36 . The method of  claim 34 , wherein the nitrogen-argon atmosphere has a nitrogen fraction of 0.2 to 0.8. 
     
     
         37 . A method of manufacturing a high manganese-nitrogen containing steel sheet, comprising:
 placing electrolytic iron, electrolytic manganese, chrome and carbon powder in a chamber;   filling the chamber with an argon-nitrogen atmosphere; and   arc-melting the electrolytic iron, electrolytic manganese, chrome and carbon powder,   wherein the manufactured steel sheet comprises:
 0.5 to 1.0 wt % of carbon, 
 10 to 20 wt % of manganese, 
 4.0 wt % or less of chrome, 
 0.02 to 0.2 wt % of nitrogen, and 
 the balance of Fe and unavoidable impurities. 
   
     
     
         38 . The method of  claim 37 , wherein the arc-melting is repeated plural times. 
     
     
         39 . The method of  claim 37 , wherein the nitrogen-argon atmosphere has a nitrogen fraction of 0.2 to 0.8. 
     
     
         40 . A method of manufacturing a high manganese-nitrogen containing steel sheet, comprising:
 placing electrolytic iron, electrolytic manganese, carbon powder, chrome and at least one of silicon, aluminum, niobium, titanium and vanadium in a chamber;   filling the chamber with an argon-nitrogen atmosphere; and   arc-melting the electrolytic iron, electrolytic manganese, carbon powder, chrome and at least one of silicon, aluminum, niobium, titanium and vanadium,   wherein the manufactured steel sheet comprises:
 0.5 to 1.0 wt % of carbon, 
 10 to 20 wt % of manganese, 
 4.0 wt % or less of chrome, 
 0.02 to 0.3 wt % of nitrogen, 
 at least one of less than 4 wt % of silicon, less than 3 wt % of aluminum, less than 0.30 wt % of niobium, less than 0.30 wt % of titanium and less than 0.30 wt % of vanadium, and 
 the balance of Fe and unavoidable impurities. 
   
     
     
         41 . The method of  claim 40 , wherein the arc-melting is repeated plural times. 
     
     
         42 . The method of  claim 40 , wherein the nitrogen-argon atmosphere has a nitrogen fraction of 0.2 to 0.8.