Wire rod excellent in wire-drawing workability and method for producing same

Abstract

Disclosed are a wire rod and a method therefor. The wire rod is excellent in wire-drawing workability, insusceptible to wire break in spite of an increase in wire-drawing rate, and reduction of area, and capable of extending a die life by suppressing die wear. The wire rod is made of steel containing C: 0.6 to 1.1%, Si: 0.1 to 2.0%, Mn: 0.1 to 1%, P: not more than 0.20%, S: not more than 0.20%, N: not more than 0.006%, Al: not more than 0.03%, and O: not more than 0.003%, the balance including Fe, and unavoidable impurities. Further, the wire rod comprises a pearlite structure wherein an area ratio of a second-phase ferrite is not more than 11.0%, and a pearlite lamellar spacing is not less than 120 μm.

1 . A wire rod made of steel comprising: 
 C: 0.6 to 1.1% (mass %, applicable to all components referred to hereunder);    Si: 0.1 to 2.0%;    Mn: 0.1 to 1%;    P: not more than 0.020% (0% exclusive);    S: not more than 0.020% (0% exclusive);    N: not more than 0.006% (0% exclusive);    Al: not more than 0.03% (0% exclusive); and    O: not more than 0.003% (0% exclusive), the balance being Fe and unavoidable impurities,    said wire rod comprising a pearlite structure wherein an area ratio of a second-phase ferrite is not more than 11.0%, and a pearlite lamellar spacing is not less than 120 μm.    
   
   
       2 . The wire rod according to  claim 1 , further comprising not more than 1.5% Cr (0% exclusive).  
   
   
       3 . The wire rod according to  claim 1 , further comprising not more than 1% Cu (0% exclusive), and/or not more than 1% Ni (0% exclusive).  
   
   
       4 . The wire rod according to  claim 1 , further comprising at least one element selected from the group consisting of not more than 0.30% (0% exclusive) V, not more than 0.1% (0% exclusive) Ti, not more than 0.10% (0% exclusive) Nb, not more than 0.5% (0% exclusive) Mo, and not more than 0.1% (0% exclusive) Zr.  
   
   
       5 . The wire rod according to  claim 1 , further comprising at least one element selected from the group consisting of not more than 5 ppm (0 ppm exclusive) Mg, not more than 5 ppm (0 ppm exclusive) Ca, and not more than 1.5 ppm (0 ppm exclusive) REM.  
   
   
       6 . The wire rod according to  claim 1 , further comprising not more than 15 ppm B.  
   
   
       7 . A method for producing a wire rod, comprising the steps of: 
 heating a steel product meeting requirements for chemical components, specified in any of  claims 1  to  6 , to a temperature in a range of 900 to 1250° C.;    hot rolling the steel product at a temperature not lower than 780° C., and finish-rolling the same at a temperature not higher than 1100° C. to be thereby formed into a wire rod;    water-cooling the wire rod to a temperature range of 750 to 950° C. before coiling the same up to be placed on conveying equipment;    cooling the wire rod at an average cooling rate of not less than 20° C./sec within 20 sec from coiling of the wire rod to thereby drop temperature of the wire rod to a minimum value point (T 1 ) in a temperature range of 550 to 630° C.; and    subsequently heating the wire rod to thereby raise the temperature of the wire rod up to a maximum value point (T 2 ) in a temperature range of 580 to 720° C., higher in value than the minimum value point (T 1 ), within 50 sec from the coiling of the wire rod.