Features and Scope:
After the hardening heat treatment and cold drawing, a high strength, toughness and plasticity certain; surface in the same state and a fully hardenability, the fatigue limit of the alloy spring considerable. But poor hardenability, mainly for the smaller size of the spring, such as voltage control spring force of the spring, usually circular machinery, or pull into a square coil spring steel wire for springs on small machines.
● Chemical Composition:
Carbon C: 0.62 ~ 0.70
Si Si: 0.17 ~ 0.37
Mn Mn: 0.50 ~ 0.80
Sulfur S: ≤0.035
Phosphorus P: ≤0.035
Chromium Cr: ≤0.25
Ni Ni: ≤0.25
Copper Cu: ≤0.25
● Mechanical Properties:
Tensile strength σb (MPa): ≥980 (100)
Yield strength σs (MPa): ≥784 (80)
Elongation δ10 (%): ≥9
Reduction of ψ (%): ≥35
Hardness: hot, ≤285HB; Cold Drawn + heat ≤321HB
● Heat treatment and microstructure specifications:
Heat treatment specifications: quenching 840 ℃ ± 20 ℃, oil cooling; tempering 500 ℃ ± 50 ℃ (when the special needs of ± 30 ℃).
● Delivery status: hot-rolled steel to heat treatment or heat treatment delivery, cold drawn steel to heat treatment delivery.