High strength steel wire for spring excellent in coiling performance and hydrogen embrittlement resistance and method for manufacturing same

Abstract

A steel wire for spring is provided which exhibits high strength even without adding a large amount of alloy elements, and is for obtaining a cold winding spring having excellent coiling performance and improved hydrogen embrittlement resistance. The steel wire for spring is characterized in that C: 0.40-0.65% (mass %), Si: 1.0-3.0%, Mn: 0.6-2.0%, P: 0.015% or less (exclusive of 0%), S: 0.015% or less (exclusive of 0%), and Al: 0.015 percent by mass or less (excluding 0%) of S, and Al: 0.001-0.10% are satisfied, with the remainder consisting of iron and inevitable impurities, tempered martensite: 70 area % or more and retained austenite: 6-15 area % with respect to the total microstructure, the prior austenite grain size number obtained by a method stipulated in JIS G 0551 is No. 10.0 or more, and the tensile strength is 1,900 MPa or more.

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