| 摘要 |
PROBLEM TO BE SOLVED: To provide a spring steel capable of providing a coil spring, which spring steel combines high strength with good corrosion fatigue property even when a temper treatment conducted after coiling is omitted during working of the spring steel into a coil spring by coiling the spring steel, and further is excellent in low temperature toughness.SOLUTION: There is provided the spring steel which contains C:0.15 to 0.40%, Si:1 to 3.5%, Mn:0.20 to 2.0%, and at least one kind selected from a group consisting of Ti:0.005 to 0.10%, Nb:0.005 to 0.05% and V:0.25%, and further contains Cr:0.05 to 1.20%, P:0.030% or less, S:0.02% or less and the balance iron with inevitable impurities and which has a carbon equivalent Ceqrepresented by the following formula (1) of 0.55 or less. Ceq=[C]+0.108×[Si]-0.067×[Mn]+0.024×[Cr]-0.05×[Ni]+0.074[V] (1) |
