20CrMnSi, is China's national standard [1] of an alloy steel grades. Unified digital code: A24202.

Standard: GB / T 3077-1988

Chemical composition:

Carbon C: 0.17 ~ 0.23

Si Si: 0.90 ~ 1.20

Manganese Mn: 0.80 ~ 1.10

Sulfur S: to allow the residual content of ≤ 0.035

Phosphorus P: allow the residual content ≤ 0.035

Chromium Cr: 0.80 ~ 1.10

Ni: to allow the residual content of ≤ 0.030

Copper Cu: to allow the residual content ≤ 0.030

● Mechanical Properties:

Tensile strength σb (MPa): ≥ 785 (80)

Yield strength σs (MPa): ≥ 635 (65)

Elongation δ5 (%): ≥ 12

Reduction of area ψ (%): ≥ 45

Impact energy Akv (J): ≥ 55

Impact toughness αkv (J/cm2): ≥ 69 (7)

Brinell hardness (HBS100/3000) (annealing or tempering condition): ≦ 207

Sample size: Sample size is 25mm rough