Grade: G20CrMo Standard: GB / T 3077-1988
Overview "
Features and application:
High hardenability, no temper brittleness, very good weldability, cold cracking tendency to form small, cutting and cold can be a good strain plasticity. General case hardening in quenched state or used for the manufacture of non-corrosive medium and temperature lower than 250 ℃, the medium containing a mixture of nitrogen and hydrogen in high pressure pipe work and a variety of fasteners, higher carburizing parts such as gears and shafts.

Chemical composition:
Carbon C: 0.17 ~ 0.24
 Si Si: 0.17 ~ 0.37
 Manganese Mn: 0.40 ~ 0.70
 Sulfur S: promised to the residual content of ≤ 0.035
 Phosphorus P: agreed residual content of ≤ 0.035
 Chromium Cr: 0.80 ~ 1.10
 Ni: to promise the residual content of ≤ 0.030
 Copper Cu: agreed residual content ≤ 0.030
 Mo Mo: 0.15 ~ 0.25 [2]
Mechanical properties:
Tensile strength σb (MPa): ≥ 885 (90)
 Yield strength σs (MPa): ≥ 685 (70)
 Elongation δ5 (%): ≥ 12
 Reduction of area ψ (%): ≥ 50
 Impact energy Akv (J): ≥ 78
 Impact toughness αkv (J/cm2): ≥ 98 (10)
 Hardness: ≤ 197HB
 Sample size: Sample size blank 15mm [3]
Heat treatment:
Heat treatment and microstructure specifications:
Standard heat treatment: quenching 880 ℃, water, oil cooling; tempering 500 ℃, water-cooled, oil-cooling.
Delivery status:
Heat treatment (normalizing, annealing, or tempering) or heat treatment delivery, delivery status should be indicated in the contract.
Heat treatment and mechanical properties:
Steel: G20CrMo
 Blank sample size / mm: 15
Heat treatment | hardening | heating temperature / ℃ | first quenching: 880
 Heat treatment | hardening | heating temperature / ℃ | second quenching: -
 Heat treatment | hardening | coolant: water, oil
 Heat treatment | Tempering | heating temperature / ℃: 500
 Heat treatment | Tempering | coolant: water, oil
 Mechanical properties | tensile strength σb / MPa | ≥: 885
 Mechanical properties | yield point σs / MPa | ≥: 685
 Mechanical properties | elongation δ5 (%) | ≥: 12
 Mechanical properties | area shrinkage ψ (%) | ≥: 50
 Mechanical properties | Impact absorbed energy AKV / J | ≥: 78
 Delivery status hardness HBS | ≥: 197