Alloy structural steel

trademark: 15CrMn
standard: GB/T 3077-1988

●chemical composition :
C : 0.12～0.18
Si: 0.17～0.37
Mn: 1.10～1.40
S : allow remains content ≤ 0.035
P : allow remains content≤ 0.035
Cr: 0.40～0.70
Ni: allow remains content≤ 0.030
Cu: allow remains content≤ 0.030

●mechanical properties:
tensile strength σ b (MPa): ≥ 785(80)
yield strength σ s (MPa): ≥ 590(60)
extensibility δ 5 (％): ≥ 12
reduction of area ψ (％): ≥ 50
ballistic work Akv (J): ≥ 47
notched bar impact strength α kv (J/cm2): ≥ 59(6)
rigidity : ≤ 179HB
specimen size: specimen size of rough 15mm

●heat treatment regime and metallurgical structure:
heat treatment regime : quenching 880℃, oil cooling ; backfire200℃, warter cooling , air cooling.

●deliver position : heat treatment(normalizing, annealing or high-temperature backfire)or no heat treatment, this should be shown on the contract.