Quenched and tempered steel wire with superior cold forging characteristics

Abstract

Disclosed is a quenched and tempered steel wire with superior cold forging characteristics, consisting essentially of 0.1-0.5 wt % of C, 1.0 wt % or less of Si, 0.2-2.5 wt % of Mn, 0.03 wt % or less of P, and 0.03 wt % of S, with the balance being Fe and inevitable impurities, which has tensile strength of 700-1300 Mpa and percent spheroidization of carbides of at least 30%. Such quenched and tempered steel wire, which is subjected to a quenching and tempering processes by high frequency induction heating in a short period, without a spheroidizing annealing process needing a long period, has forging characteristics equal or superior to those of spheroidizing annealed steel wire, thus increasing productivity. Therefore, the quenched and tempered steel wire is applicable to make various bolts and shafts as parts for machine structures requiring high strengths.

1 . A quenched and tempered steel wire with superior cold forging characteristics, comprising 0.1-0.5 wt % of C, 1.0 wt % or less of Si, 0.20-2.5 wt % of Mn, 0.03 wt % or less of P, and 0.03 wt % or less of S, with the balance being Fe and inevitable impurities, which has tensile strength in a range of 700-1300 Mpa and percent spheroidization of carbides not less than 30%.  
   
   
       2 . The quenched and tempered steel wire as defined in  claim 1 , further comprising at least one component selected from among 0.05-2.0 wt % of Cr, 0.05-1.5 wt % of Mo and 0.0003-0.0050 wt % of B.  
   
   
       3 . A quenched and tempered steel wire with superior cold forging characteristics, comprising the steel wire of  claim 1  or  2  stretched.