| 摘要 |
PURPOSE: To provide a quenched and tempered steel wire having high strength and superior cold heading characteristics manufactured by skipping a spheroidizing annealing process, performing quenching and tempering heat treatments on a steel wire and cold heading the quenching and tempering heat treated steel wire. CONSTITUTION: The steel wire for cold heading is a quenched and tempered steel wire containing 0.10 to 0.40 wt.% of C, 1.0 wt.% or less of Si, 0.30 to 2.0 wt.% of Mn, 0.03 wt.% or less of P, 0.03 wt.% or less of S and the balance being Fe and inevitable impurities and having a tensile strength of 70 to 130 kgf/mm¬2, wherein a ratio of reduction of area(δ,%) to tensile strength(TS) is 0.4 to 1.2, and wherein the steel wire further contains one or more components selected from 0.05 to 2.0 wt.% of Cr, 0.05 to 1.5 wt.% of Mo and 0.0003 to 0.0050 wt.% of B.
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