International brands of international standard 85 # spring steel Standard: GB / T 1222-1984 Features and Scope: 85 # steel strength and hardness than other carbon structural steel to be high, but the flexibility is slightly lower, its revenue performance and 65,70,75 , 80 steel were similar, hardenability is not high, the critical quenching in oil diameter of 9-23mm. 85 gauge steel for the manufacture of small cross-sectional size and strength to withstand the vibration of the spring is not too high, such as railway vehicles, cars, tractors and general machinery, the flat springs and circular spiral springs and other uses such as spring steel wire and strip. Chemical composition: Mechanical Properties: Carbon C: 0.82 ~ 0.90 Tensile strength σb (MPa): ≥ 1127 (115) Si Si: 0.17 ~ 0.37 Yield strength σs (MPa): ≥ 980 (100) Manganese Mn: 0.50 ~ 0.80 extensor growth rate δ10 (%): ≥ 6 Sulfur S: ≤ 0.035 Reduction ψ (%): ≥ 30 Phosphorus P: ≤ 0.035 Hardness: hot ≤ 302HB; Cold Drawn + heat treatment ≤ 321HB; annealed steel ≤ 255 Chromium Cr: ≤ 0.25 Ni-Ni: ≤ 0.25 Copper Cu: ≤ 0.25 sample blank Dimensions / mm: Sample Heat treatment and microstructure specifications: Heat treatment specifications: quenching 820 ℃ ± 20 ℃, oil cooling; tempering 480 ℃ ± 50 ℃ (special when required, ± 30 ℃). Delivery status: hot-rolled steel to heat treatment or heat treatment delivery, cold drawn steel to heat treatment delivery