Material Name: SUP9A spring steel ● Features and Scope: high strength, ductility and toughness, good hardenability, heat sensitivity lower than manganese than the high manganese steel, silico-manganese steel decarburization tendency than the small, back Fire brittleness. For a vehicle, the load on the production of industrial tractors heavier, larger stress larger diameter coil spring and the spring. Spring steel ● Chemical Composition: Carbon C: 0.56 ~ 0.64 Si Si: 0.17 ~ 0.37 Manganese Mn: 0.70 ~ 1.00 Sulfur S: ≤ 0.030 Phosphorus P: ≤ 0.030 Chromium Cr: 0.70 ~ 1.00 Ni-Ni: ≤ 0.35 Copper Cu: ≤ 0.25 ● Mechanical Properties: Tensile strength σb (MPa): ≥ 1225 (125) Conditions yield strength σ0.2 (MPa): ≥ 1078 (110) Elongation δ5 (%): ≥ 9 (for reference) section shrinkage ψ (%): ≥ 20 Hardness: hot, ≤ 321HB; Cold Drawn + heat treatment, ≤ 321HB ● Heat treatment and microstructure specifications: Heat treatment specifications: quenching 830 ~ 860 ℃, oil cooling; tempering 460 ~ 520 ℃. ● Delivery status: hot-rolled steel to heat treatment or heat treatment delivery, cold drawn steel to heat treatment delivery.