Material Name: Alloy structural steel 
 Grade: 40CrV 
 Standard: GB / T 3077-1988 
 ● Features and Scope: 
 Higher hardenability by quenching after high-intensity and yield point, the performance is better than 40Cr steel. For important parts such as crankshafts, gears, putting, by the strong double-headed bolts, screws, motorcycle connecting rods, propeller, bearing brackets, beams, etc. 
 ● Chemical Composition: 
 Carbon C: 0.37 ~ 0.44 
 Si Si: 0.17 ~ 0.37 
 Manganese Mn: 0.50 ~ 0.80 
 S S: to allow the residual content ≤ 0.035 
 Phosphorus P: allow the residual content ≤ 0.035 
 Chromium Cr: 0.80 ~ 1.10 
 Ni: to allow the residual content ≤ 0.030 
 Copper Cu: ≤ 0.030 to allow the residual content 
 Vanadium V: 0.10 ~ 0.20 
 ● Mechanical Properties: 
 Tensile strength σb (MPa): ≥ 885 (90) 
 Yield strength σs (MPa): ≥ 735 (75) 
 Elongation δ5 (%): ≥ 10 
 Reduction of area ψ (%): ≥ 50 
 Impact energy Akv (J): ≥ 71 
 Impact toughness αkv (J/cm2): ≥ 88 (9) 
 Hardness: ≤ 241HB 
 Sample size: Sample size of 25mm rough 
 ● Heat treatment and microstructure specifications: 
 Standard heat treatment: quenching 880 ℃, oil-cooling; tempering 650 ℃, water-cooled, oil-cooling. 

 ● Delivery status: to heat treatment (normalizing, annealing, or tempering) or heat treatment delivery, delivery status should be indicated in the contract.