Wire rod having good superior surface properties, high strength, and high toughness, and a method for manufacturing same

Abstract

Provided is a wire rod having high strength and high toughness, which suppresses the generation of surface oxide and has superior surface properties through uniform oxide formation, and to a method for manufacturing same. For this purpose, a wire rod comprising 0.005˜ to 0.02 wt. % of Sb, having superior surface properties, high strength and high toughness, and a method for manufacturing same are provided.

1 . A wire rod having superior surface properties, high strength, and high toughness, the wire rod comprising: 0.005 to 0.02% of antimony (Sb), in terms of weight percentage. 
     
     
         2 . The wire rod of  claim 1 , wherein the wire rod includes antimony (Sb) oxides, the antimony (Sb) oxides including Sb 2 O 5 . 
     
     
         3 . The wire rod of  claim 2 , wherein the antimony (Sb) oxides have an average grain diameter of 20 to 50 nm. 
     
     
         4 . The wire rod of  claim 2 , wherein an amount of the antimony (Sb) oxides distributed per μm 2  is 50 to 100. 
     
     
         5 . The wire rod of  claim 1 , further comprising carbon C: 0.25 to 0.45%, Si: 0.1 to 0.2%, and Mn: 0.1 to 0.7%, in terms of weight percentage. 
     
     
         6 . The wire rod of  claim 1 , wherein in a microstructure of the wire rod, a relative area of ferrite is 70% or more and pearlite occupies a remainder of the area thereof. 
     
     
         7 . The wire rod of  claim 6 , wherein an average grain size of ferrite is 10 to 20 μm and an average grain size of pearlite is 20 to 25 μm. 
     
     
         8 . The wire rod of  claim 1 , wherein the wire rod has scale formed on a surface thereof at a thickness of 20 to 150 μm. 
     
     
         9 . The wire rod of  claim 1 , wherein the wire rod has a tensile strength of 600 to 900 MPa and an elongation of 25% or more. 
     
     
         10 . A method for manufacturing a wire rod having superior surface properties, high strength, and high toughness, the method comprising:
 reheating steel including 0.005 to 0.02% of antimony (Sb), in terms of weight percentage;   wire rod-rolling the reheated steel at 700 to 1100° C.; and   performing cooling at a cooling rate of 0.5 to 2° C./s after the wire rod-rolling.   
     
     
         11 . The method of  claim 10 , wherein the steel further includes C: 0.25 to 0.45%, Si: 0.1 to 0.2%, and Mn: 0.1 to 0.7%, in terms of weight percentage. 
     
     
         12 . The method of  claim 10 , further comprising: performing wire drawing after the performing of cooling.