| 摘要 |
The present specification provides a spring of greater strength. A spring 2 disclosed in the present specification comprises a steel material layer 12 and a compound layer 14 containing nitride and formed on a surface of the steel material layer 12. The steel material layer 12 contains, in mass percent, C: 0.55 to 0.75, Si: 1.50 to 2.50, Mn: 0.30 to 1.00, Cr: 0.80 to 2.00, W: 0.05 to 0.30, and iron and inevitable impurities as remainders. Carbide precipitated in the steel. material layer has an average length of 0.12 mum or less and an average width of 0.04 mum or less.
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