Wire rod and steel wire for springs having excellent corrosion fatigue resistance properties, and method for producing same

A method for producing a steel wire for a spring having an excellent corrosion fatigue resistance property, the method comprising:

• heating, at 900 to 1050° C., a billet containing, by wt %, C:
• 0.40 to 0.70%, Si:
• 1.20 to 2.30%, Mn:
• 0.20 to 0.80%, Cr:
• 0.20 to 0.80%, P:
• 0.015% or less, S:
• 0.015% or less, N:
• 0.010% or less, and a balance of Fe and other unavoidable impurities, and further containing one or two of V:
• 0.01 to 0.20% and Nb:
• 0.01 to 0.10%, V and Nb satisfying the following Relational Expression 1;
• finishing rolling and winding the heated billet at 800 to 1000° C. to obtain a wound coil;
• performing primary cooling on the wound coil at a cooling rate of 2.0 to 10° C./s up to Ar1-40° C. and performing secondary cooling on the wound coil at a cooling rate of 0.3 to 1.8° C./s in a temperature range of (Ar1-40° C.) to (Ar1-140° C.);
• drawing the steel wire subjected to the primary and secondary cooling to obtain a steel wire;
• heating the steel wire at 850 to 1000° C. and holding the steel wire for 1 to 300 seconds;
• oil-cooling the heated and held steel wire up to 25 to 80° C.;
• and
• tempering the oil-cooled steel wire at 350 to 500° C.,
• [V]+[Nb]≥0.08 (where, a content of each of V and Nb refers to wt %). [Relational Expression 1]