Standard: GB / T 3077-1988

Chemical Composition:
C: 0.17 ~ 0.23
Si: 0.17 ~ 0.37
Mn: 0.60 ~ 0.95
S: ≤ 0.035
P: ≤ 0.035 
Cr: 0.40 ~ 0.70
Ni: 0.35 ~ 0.75
Cu: ≤ 0.030 
Mo: 0.20 ~ 0.30
Mechanical Properties:
Tensile strength σb (MPa): ≥ 980 (100)
Yield strength σs (MPa): ≥ 785 (80)
Elongation δ5 (%): ≥ 9
Reduction of area ψ (%): ≥ 40
Impact energy Akv (J): ≥ 47
Impact toughness αkv (J/cm2): ≥ 59 (6)
Hardness: ≤ 197HB