Argon oxygen decarburization refining method for molten austenitic stainless steel

Abstract

An argon oxygen decarburization (AOD) refining method for molten austenitic stainless steel includes, preparing molten austenitic stainless steel in an electric arc furnace, pouring the molten austenitic stainless steel into an AOD refining furnace by adjusting a carbon concentration of the molten austenitic stainless steel to 2.0 wt % to 2.5 wt %, decarburizing the poured molten austenitic stainless steel by blowing oxygen (O 2 ) and argon (Ar) thereinto, and reduction-decarburizing the decarburized molten austenitic stainless steel by blowing argon (Ar) thereinto.

1 . An argon oxygen decarburization (AOD) refining method for molten austenitic stainless steel comprising:
 preparing molten austenitic stainless steel in an electric arc furnace;   pouring the molten austenitic stainless steel into an AOD refining furnace by adjusting a carbon concentration of the molten austenitic stainless steel to 2.0 wt % to 2.5 wt %;   decarburizing the poured molten austenitic stainless steel by blowing oxygen (O 2 ) and argon (Ar) thereinto; and   reduction-decarburizing the decarburized molten austenitic stainless steel by blowing argon (Ar) thereinto.   
     
     
         2 . The AOD refining method for molten austenitic stainless steel of  claim 1 , wherein the reduction-decarburizing is performed under conditions in which a flow rate of the argon is 50 Nm 3 /min to 55 Nm 3 /min. 
     
     
         3 . The AOD refining method for molten austenitic stainless steel of  claim 1 , wherein the decarburizing is performed by gradually reducing a flow rate of the oxygen and by gradually increasing a flow rate of the argon. 
     
     
         4 . The AOD refining method for molten austenitic stainless steel of  claim 3 , wherein an initial flow rate of the oxygen is 140 Nm 3 /min to 170 Nm 3 /min. 
     
     
         5 . The AOD refining method for molten austenitic stainless steel of  claim 1 , wherein a nitrogen concentration of the molten austenitic stainless steel after the reduction-decarburizing is 75 ppm or less. 
     
     
         6 . The AOD refining method for molten austenitic stainless steel of  claim 1 , wherein a component of the molten austenitic stainless steel after the reduction-decarburizing includes, by wt %, C: 0.003% to 0.16%, Si: 0.2% to 0.7%, Mn: 1.0% to 5.0%, P: 0.03% or less, S: 0.02% or less, Cr: 16% to 18%, Ni: 7% to 9%, Mo: 0.001% to 0.200%, N: 75 ppm by weight or less, iron (Fe) as a remainder thereof, and other unavoidable impurities.