Chemical composition:
Chemical Composition
C Si Mn P S Ni Cr Cu
≤
80 0.77 to 0.85 0.17 to 0.37 0.50 to 0.80 0.30 0.25 0.25 0.035 0.035
85 0.82 to 0.90 0.17 to 0.37 0.50 to 0.80 0.30 0.25 0.035 0.035

Mechanical properties:
Grades blank sample
Size
/ mm heat treatment process of the mechanical properties of the steel hardness delivery status
/ HBS
Normalizing quenching and tempering σb / MPa σs / MPa δ5 (%) ψ (%) Ak / J ≤
≥ No heat annealed steel
80 samples 820 4,801,080,930,630,285,241
85 samples 820 4,801,130,980,630,302,255

Characteristics and Uses:
80 and 65 gauge steel performance similar to its flexibility somewhat less than 65 steel, high strength, low hardenability, usually in the quenched and tempered state. Is not used in the manufacture of high strength, smaller cross-sectional dimensions of the coil spring, plate spring, the wear of mechanical parts.
85: high wear resistance of high carbon steel is slightly higher strength than No. 70, while the elasticity is slightly lower, similar to other properties, hardenability poor. Sectional dimensions for the manufacture of small, not too high to withstand vibration strength springs, automotive and railway vehicles and general machinery spring, circular spiral spring.