Alloy structural steel: 4340 (40crni2moa)
U.S. brand numbers: SAE4340, AISI4340
Implementation standard: ASTM A29/A29M-04
Chemical composition:
Carbon C: 0.38-0.43
Si: 0.15-0.35
Mn: 0.60-0.90
Sulfur S: Allowable Residual Content ≤ 0.040
Phosphorus p: allowable residual content ≤ 0.035
Cr: 0.60-0.90
Ni: 1.65 ~ 2.00
Cu: Allowable Residual Content ≤ 0.025
Mo: 0.20-0.30
Mechanical properties:
Tensile strength σ b (MPa): ≥ 980 (100)
Yield strength σ s (MPa): ≥ 835 (85)
Elongation Δ 5 (%): ≥ 12
Section shrinkage Ψ (%): ≥ 55
Akv (j) of impact power: ≥ 78
Impact toughness value α kv (j/cm2): ≥ 98 (10)
Hardness: ≤ 269hb
Sample size: the sample blank size is 25 mm.
Heat Treatment Specification and Metallographic Structure;
Heat treatment specification: quenching 850℃, oil cooling; Tempering 600℃, water cooling, oil cooling.
Delivery status: delivery in heat treatment (normalizing, high temperature tempering) or annealing status