| 摘要 |
PROBLEM TO BE SOLVED: To provide a high strength spring steel wire capable of making high strength compatible with satisfactory cold spring formability. SOLUTION: The high strength spring steel wire has a composition containing, by mass, 0.55 to 0.65% C, 1.2 to 2.5% Si, 0.3 to 0.6% Mn and 0.4 to 2.0% Cr, and in which the content of P is limited to <=0.015%, and S to <=0.015%, and, if required, containing one or two kinds selected from 0.05 to 2.0% Mo and 0.05 to 0.3% V (wherein, the content of Mn+V is <=0.6%), and in which the size of nonmetallic inclusions is <=15μm, and has tensile strength of >=1,960 MPa and a yield ratio (σ0.2 /σB) of 0.8 to 0.9, or has a yield ratio of >0.9 and a retained austenite content of <=6%, and further has an old austenite grain size number of No.>=11.
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