High-strength steel wire material exhibiting excellent cold-drawing properties, and high-strength steel wire

Abstract

Provided are: a high-strength steel wire material which exhibits excellent cold-drawing properties and a high prescribed strength; a high-strength steel wire produced from this high-strength steel wire material; and a zinc-plated high-strength steel wire. This high-strength steel wire material is characterized by respectively including 0.80-1.3% of C, 0.1-1.5% of Si, 0.1-1.5% of Mn, more than 0% but not more than 0.03% of P, more than 0% but not more than 0.03% of S, 0.02-0.2% of Ti, 0.01-0.10% of Al, and 0.001-0.006% of N, the remainder comprising iron and unavoidable impurities. The high-strength steel wire material is further characterized in that the relationship in formula (1), namely 0.05%≧[Ti*]≧(0.0023 [C]) (with the caveat that [Ti*]=(the total amount of Ti−the total amount of Ti in compounds having a size of at least 0.1 μm), and [C] represents the carbon content (in mass %)), is satisfied.

1 . A high-strength steel wire rod having good rod drawability, the steel wire rod comprising:
 C: 0.80 to 1.3% by mass;   Si: 0.1 to 1.5% by mass;   Mn: 0.1 to 1.5% by mass;   P: more than 0% and 0.03% or less by mass;   S: more than 0% and 0.03% or less by mass;   Ti: 0.02 to 0.2% by mass;   Al: 0.01 to 0.10% by mass;   N: 0.001 to 0.006% by mass; and   iron and inevitable impurities,   
       wherein a relationship of Formula (1) is satisfied:
   0.05%≧[Ti*]≧(0.0023×[C])  (1)
 
 where [Ti*] represents “a total amount of Ti−an amount of Ti in compounds having a size of 0.1 μm or more”, and [C] represents carbon content (by mass percent)). 
 
     
     
         2 . The high-strength steel wire rod according to  claim 1 , wherein a microstructure of the steel wire rod includes a pearlite phase having an area ratio of 90% or more, and proeutectoid cementite has a maximum length of 15 μm or less. 
     
     
         3 . The high-strength steel wire rod according to  claim 1 , wherein an amount of dissolved N is more than 0% and 0.0005% or less. 
     
     
         4 . The high-strength steel wire rod according to  claim 2 , wherein the amount of dissolved N is more than 0% and 0.0005% or less. 
     
     
         5 . The high-strength steel wire rod according to  claim 1 , further comprising one or more of B, Cr, V, and M, M representing at least one element selected from the group consisting of Ni, Cu, Mo, Co, and Nb, in the proportions of
 B: more than 0% and 0.010% or less by mass,   Cr: more than 0% and 0.5% or less by mass,   V: more than 0% and 0.2% or less by mass,   Ni: more than 0% and 0.5% or less by mass,   Cu: more than 0% and 0.5% or less by mass,   Mo: more than 0% and 0.5% or less by mass,   Co: more than 0% and 1.0% or less by mass, and   Nb: more than 0% and 0.5% or less by mass.   
     
     
         6 . A high-strength steel wire that is produced through wire-drawing of the high-strength steel wire rod according to  claim 1 . 
     
     
         7 . A high-strength steel wire that is produced through wire-drawing of the high-strength steel wire rod according to  claim 5 . 
     
     
         8 . A high-strength galvanized steel wire produced by performing hot-dip galvanization on the high-strength steel wire according to  claim 6 , wherein the high-strength galvanized steel wire has a tensile strength TS equal to or higher than tensile strength TS* defined by Formula (2):
   TS*=−87.3 D +2234 (MPa)  (2)
   where D represents wire diameter (mm) of the high-strength galvanized steel wire.   
     
     
         9 . A high-strength galvanized steel wire produced by performing hot-dip galvanization on the high-strength steel wire according to  claim 7 , wherein the high-strength galvanized steel wire has a tensile strength TS equal to or higher than tensile strength TS* defined by Formula (2):
   TS*=−87.3 D +2234 (MPa)  (2)
   where D represents wire diameter (mm) of the high-strength galvanized steel wire.