40CrMn 

 Application examples 40CrMn, the Chinese national standard [1] of an alloy structural steel grades. Uniform digital code: A22402. Standard: GB / T 3077-1988 
 40CrMn alloy steel 
 Chemical composition 
 Mass fraction (%): C C: 0.37 ~ 0.45 Si Si: 0.17 ~ 0.37 Manganese Mn: 0.90 ~ 1.20 S S: to allow the residual phosphorus content ≤ 0.035 P: ≤ 0.035 to allow the residual content of chromium Cr: 0.90 ~ 1.20 Ni: to allow residual content ≤ 0.030 Copper Cu: ≤ 0.030 to allow the residual content 
 Mechanical Properties 
 【Size】 25mm 【sample blank] quenching heat treatment temperature (℃): 840; Coolant: Oil-tempered heating temperature (℃): 550; coolant: water, oil and mechanical properties] [tensile strength σb (MPa) : ≥ 980 (100) yield strength σs (MPa): ≥ 835 (85) Elongation δ5 (%): ≥ 9 Reduction of area ψ (%): ≥ 45 Impact energy Akv (J): ≥ 47 impact toughness αkv (J/cm2): ≥ 59 (6) Brinell hardness (HBS100/3000) (annealing or tempering state): ≦ 229 Delivery status: to heat treatment (normalizing, annealing, or tempering) or heat treatment state of delivery, delivery status should be indicated in the contract