25CrMnSi, is a Chinese national standard alloy steel grades. Unified digital code: A24252.

Standard: GB / T 3077-1988

Chemical composition of mass fraction (%):

Carbon C: 0.22 ~ 0.28

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
Sample size [blank]

25mm

[Heat]

Quenching temperature (℃): 880; Coolant: Oil

Tempering heating temperature (℃): 480; coolant: water, oil

[Mechanical properties]

Tensile strength σb (MPa): ≥ 1080 (110)

Yield strength σs (MPa): ≥ 885 (90)

Elongation δ5 (%): ≥ 10

Reduction of area ψ (%): ≥ 40

Impact energy Akv (J): ≥ 39

Impact toughness αkv (J/cm2): ≥ 49 (5)

Brinell hardness (HBS100/3000) (annealing or tempering condition): ≦ 217

Standard heat treatment: quenching 880 ℃, oil cooling; tempering 480 ℃, 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.

Main features higher strength than 20CrMnSi, toughness is poor. After heat treatment, strength, ductility, toughness is good