20CrMn, is a Chinese national standard alloy structural steel grades. Uniform digital code: A22202. 

 Standard: GB / T 3077-1988 

 Chemical composition 
 Mass fraction (%): 

 Carbon C: 0.17 ~ 0.23 

 Si Si: 0.17 ~ 0.37 

 Manganese Mn: 0.90 ~ 1.20 

 S S: to allow the residual content ≤ 0.035 

 Phosphorus P: allow the residual content ≤ 0.035 

 Chromium Cr: 0.90 ~ 1.20 

 Ni: to allow the residual content ≤ 0.030 

 Copper Cu: ≤ 0.030 to allow the residual content 

 Mechanical Properties 
 Sample size [blank] 

 15mm 

 [Heat treatment] 

 Quenching temperature (℃): 850; Coolant: Oil 

 Tempering heating temperature (℃): 200; coolant: water, air 

 [Mechanical Properties] 

 Tensile strength σb (MPa): ≥ 930 (95) 

 Yield strength σs (MPa): ≥ 735 (75) 

 Elongation δ5 (%): ≥ 10 

 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): ≦ 187 

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

 Key Features 
 Case-hardened steel, strength, high toughness, good hardenability. Obtained after heat treatment is better than 20Cr. Quenching deformation is small, good low temperature toughness, good machinability; but welding performance is low. Generally quenched after carburizing or use. 

 Application examples 
 Used in the manufacture and large cross-section of the quenched and tempered heavy parts and a small section of carburized parts, but also for the manufacture of medium load, the smaller the impact of small parts, instead of 20CrNi use, such as gears, shafts, friction wheel, worm governor sleeve, etc.