Steel wire for mechanical structural parts

Abstract

An object of the present invention is to provide a steel wire for mechanical structural parts that is reduced in deformation resistance and improved in crack resistance during cold working, and thus exhibits excellent cold workability. The steel wire for mechanical structural parts of the present invention is a steel wire containing, in mass %, 0.3 to 0.6% of C, (105 to 0.5% of Si, 0.2 to 1.7% of Mn, more than 0% and 0.03% or less of P, 0.001 to 0.05% of S, 0.005 to 0.1% of Al, and 0 to 0.015% of N, the balance being iron and inevitable impurities, wherein steel of the steel wire has a metal structure formed of ferrite and cementite, and the number proportion of cementite particles present in ferrite grain boundaries is 40% or more based on the total number of cementite particles.

1 . A steel wire, comprising, in mass %,
 3 to 0.6% of C,   0.05 to 0.5% of Si,   0.2 to 1.7% of Mn,   more than 0% and 0.03% or less of P,   0.001 to 0.05% of S,   0.005 to 0.1% of Al,   0 to 0.015% of N, and   iron,   wherein steel of the steel wire has a metal structure comprising ferrite and cementite, and a number proportion of cementite particles present in ferrite grain boundaries is 40% or more based on a total number of cementite particles.   
     
     
         2 . The steel wire according to  claim 1 , further comprising, in mass %,
 at least one component selected from the group consisting of:
 more than 0% and 0.5% or less of Cr, 
 more than 0% and 0.25% or less of Cu, 
 more than 0% and 0.25% or less of Ni, 
 more than 0% and 0.25% or less of Mo, and 
 more than 0% and 0.01% or less of B. 
   
     
     
         3 . The steel wire according to  claim 1 , wherein an average equivalent circle diameter of bcc-Fe crystal grains in the metal structure is 30 μm or less. 
     
     
         4 . The steel wire according to  claim 2 , wherein an average equivalent circle diameter of bcc-Fe crystal grains in the metal structure is 30 μm or less.