Method of producing steel wire

Abstract

Provided is a production method in which a steel having a good tensile strength can be produced with a small processing energy. The method is a method of producing a steel wire, the method including: a pre-drawing process in which a high-carbon steel wire containing 0.90 to 1.20% by mass of carbon is subjected to a drawing to obtain an intermediate wire; a heat treatment process in which the intermediate wire is subjected to a patenting heat treatment to obtain a heat treated wire; and a final drawing process in which the heat treated wire is subjected to a drawing to obtain a steel wire, wherein the amount εf of drawing in the final drawing process which satisfies the relation represented by the following formula: εf= 2 ln ( D 0/ Df ) (wherein Df represents the final diameter of the steel wire obtained in the final drawing process, D0 represents the diameter of the heat treated wire before the final drawing process and ln represents natural logarithm) is 2.50 to 3.10.

1 . A method of producing a steel wire, the method including: a pre-drawing process in which a high-carbon steel wire containing 0.90 to 1.20% by mass of carbon is subjected to a drawing to obtain an intermediate wire; a heat treatment process in which the intermediate wire is subjected to a patenting heat treatment to obtain a heat treated wire; and a final drawing process in which the heat treated wire is subjected to a drawing to obtain a steel wire, wherein the amount εf of drawing in the final drawing process which satisfies the relation represented by the following formula:
   ε f= 2 ln ( D 0/ Df )
 
 
       (wherein Df represents the final diameter of the steel wire obtained in the final drawing process, D0 represents the diameter of the heat treated wire before the final drawing process and ln represents natural logarithm) is 2.50 to 3.10. 
     
     
         2 . The method of producing a steel wire of  claim 1 , wherein the metal structure of the high-carbon steel wire is pearlite. 
     
     
         3 . The method of producing a steel wire of  claim 1 , wherein the diameter of a steel wire obtained in the final drawing process is 0.05 to 0.50 mm. 
     
     
         4 . The method of producing a steel wire of  claim 2 , wherein the tensile strength TSf of the steel wire obtained in the final drawing process, the tensile strength TS of the heat treated wire and the εf satisfy the relation represented by the following formula:
   TS×exp(0.24 ×εf )<TS f <TS×exp(0.30× εf ).
 
 
     
     
         5 . The method of producing a steel wire of  claim 4 , wherein the TSf is 2700 to 3300 MPa. 
     
     
         6 . The method of producing a steel wire of  claim 4 , wherein a high-carbon steel wire containing 0.90 to 1.05% by mass of carbon is subjected to a drawing to obtain an intermediate wire; the εf is 2.70 to 3.05; and the TSf is 2700 to 3200 MPa.