Material Name: 85 spring steel

Standard: GB / T 1222-1984
● Features and Scope:
No. 65, 70 steel similar performance and high strength, mainly for the flat leaf spring to withstand vibration and circular coil spring on the smaller size springs, such as automobiles, tractors and other machinery or train.
● Chemical Composition:
Carbon C: 0.82 ~ 0.90
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): ≥1127 (115)
Yield strength σs (MPa): ≥980 (100)
Elongation δ10 (%): ≥6
Reduction of ψ (%): ≥30
Hardness: hot, ≤302HB; Cold Drawn + heat, ≤321HB
● Heat treatment and microstructure specifications:
Heat treatment specifications: quenching 820 ℃ ± 20 ℃, oil cooling; tempering 480 ℃ ± 50 ℃ (when special needs, ± 30 ℃).
● Delivery status: hot-rolled steel to heat treatment or heat treatment delivery, cold drawn steel to heat treatment delivery.