High strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance

Abstract

Disclosed herein is a high strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance. The steel wire comprises, by mass, 0.4 to 0.60% of C, 1.7 to 2.5% of Si, 0.1 to 0.4% of Mn, 0.5 to 2.0% of Cr, 0.015% or less of P (exceeding 0%), 0.015% or less of S (exceeding 0%), 0.006% or less of N (exceeding 0%), 0.001 to 0.07% of Al, and the remainder being Fe and unavoidable impurities. The steel wire has a structure wherein prior austenite has an average grain size of 12 mum or less, and retained austenite exists in an amount of 1.0 to 8.0 vol. % with respect to a whole structure of the steel wire. The retained austenite has an average grain size of 300 nm or less and a maximum grain size of 800 nm or less. The steel has a tensile strength of 1,900 MPa or more.

Description

technical field [0001] The present invention relates to a high-strength spring steel wire having excellent coilability and resistance to hydrogen embrittlement, and more particularly, to a spring steel wire having coilability and resistance to hydrogen embrittlement in a high-strength range of tensile strength of 1,900 MPa or more Reinforced spring steel wire. Background technique [0002] The need to reduce the weight of motor vehicles is accompanied by reductions in the size and thickness of vehicle components. In this regard, vehicle floor members such as suspension springs are required to have high strength. However, since an increase in steel strength generally decreases corrosion fatigue properties while increasing atmospheric fatigue properties, it is difficult to simultaneously improve atmospheric fatigue properties and corrosion fatigue properties together with steel strength. [0003] In order to improve corrosion fatigue properties, several methods have been sug...

AI Technical Summary

Problems solved by technology

However, in the related art, for a high-strength spring steel wire having a tensile strength of 1,900 MPa or more, a method of simultaneously enhancing coilability and resistance to hydrogen embrittlement has not been proposed

Specifically, there is still no proposed technology that can simultaneously enhance coilability and hydrogen embrittlement resistance without sacrificing the advantages of cold-coiled coil springs, such as low cost and wide applicability.

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