Chemical composition and mechanical properties of 20CrMn alloy structural steel

20CrMn is a grade of alloy structural steel stipulated by the Chinese national standard. Unified digital code: A22202. Standard: GB/T 3077. 20CrMn is a carburizing steel, which can also be used as a quenched and tempered steel, and its hardenability is similar to that of 20CrNi.

20CrMn alloy structural steel is used as shafts and connecting rods working at high speed and high bending load, gear shafts, gears, water pump rotors, clutches, small shafts and mandrels working at high speed and high load without strong impact load.

20CrMn alloy steel chemical composition (%):
Carbon C: 0.17-0.23
Silicon Si: 0.17-0.37
Manganese Mn: 0.90-1.20
Sulfur S: allowable residual content ≤ 0.035
Phosphorus P: Allowable residual content≤0.035
Chromium Cr: 0.90-1.20
Nickel Ni: Allowable residual content≤0.030
Copper Cu: Allowable residual content≤0.030

Mechanical properties of 20CrMn steel:
[Sample blank size]: 15mm
Heat treatment:
Quenching heating temperature (℃): 850; Coolant: oil
Tempering heating temperature (℃): 200; coolant: water, air
Tensile strength σb (MPa): ≥930(95)
Yield strength σs (MPa): ≥735(75)
Elongation δ5 (%): ≥10
Area shrinkage ψ (%): ≥45
Impact energy Akv (J): ≥47
Impact toughness value αkv (J/cm2): ≥59(6)
Brinell hardness: (HBS100/3000) (annealed or tempered at high temperature): ≦187
Delivery status: Delivered with heat treatment (normalizing, annealing or high temperature tempering) or without heat treatment, and the delivery status should be specified in the contract.

Application of 20CrMn alloy structural steel:
20CrMn alloy steel is used for manufacturing heavy-duty large-section quenched and tempered parts and small-section carburized parts. It can also be used to manufacture small and medium-sized parts with medium load and small impact, instead of 20CrNi, such as gears, shafts, friction wheels, and worm speed governors. sleeve, etc.