High-strength ultrathin steel wire and method of manufacturing the same

Abstract

The present invention provides a steel wire, including chemical components of: C: 0.7-1.2 mass %; Si: 0.05-2.0 mass %; and Mn: 0.2-2.0 mass %, with a balance including Fe and inevitable impurities, in which the steel wire has a pearlite structure, the average C concentration at a center portion of a ferrite phase in an outermost layer of the steel wire is 0.2 mass % or lower, and a residual compressive stress in the longitudinal direction of the steel wire in the outermost layer is 600 MPa or more.

1 . A steel wire including the chemical components of:
 C: 0.7-1.2 mass %;   Si: 0.05-2.0 mass %; and   Mn: 0.2-2.0 mass %,   with a balance including Fe and inevitable impurities, wherein   the steel wire has a pearlite structure,   an average C concentration at a center portion of a ferrite phase in an outermost layer of the steel wire is 0.2 mass % or lower, and   a residual compressive stress in a longitudinal direction of the steel wire in the outermost layer is 600 MPa or more.   
     
     
         2 . The steel wire according to  claim 1 , further including one or more chemical components of:
 Cr: 0.05-1.0 mass %;   Ni: 0.05-1.0 mass %;   V: 0.01-0.5 mass %;   Nb: 0.001-0.1 mass %;   Mo: 0.01-0.1 mass %; and   B: 0.0001-0.01 mass %.   
     
     
         3 . The steel wire according to  claim 1  or  2 , wherein
 the steel wire is a high-strength ultrathin steel wire having a tensile strength of 4500 MPa or more. 
 
     
     
         4 . The steel wire according to  claim 3 , wherein
 the high-strength ultrathin steel wire is a steel cord.   
     
     
         5 . The steel wire according to  claim 3 , wherein
 the high-strength ultrathin steel wire is a saw wire.   
     
     
         6 . A method of manufacturing a steel wire having a tensile strength of 4500 MPa or more, the steel wire including the chemical components of:
 C: 0.7-1.2 mass %;   Si: 0.05-2.0 mass %; and   Mn: 0.2-2.0 mass %,   with a balance including Fe and inevitable impurities,   the method including:   applying a patenting treatment to the steel wire to generate a pearlite structure,   drawing the steel wire so as to control an average C concentration at a center portion of a ferrite phase in the pearlite structure in an outermost layer of the steel wire to be 0.2 mass % or lower, and   applying a residual compressive stress of 600 MPa or more to the steel wire.