38CrSi, alloy structural steel.

Unified digital code: A21382

Standard: GB / T 3077-1988

Chemical composition
(Wt) (%)
Carbon C: 0.35 ~ 0.43

Si Si: 1.00 ~ 1.30

Manganese Mn: 0.30 ~ 0.60

Sulfur S: to allow the residual content of ≤ 0.035

Phosphorus P: allow the residual content ≤ 0.035

Chromium Cr: 1.30 ~ 1.60

Ni: to allow the residual content of ≤ 0.030

Copper Cu: to allow the residual content ≤ 0.030

Key Features
This is a high strength, moderate toughness of steel, its hardenability slightly better than 40Cr in the critical oil quenching diameter 25 ~ 83.5mm; steel cutting still be good, but the tendency to temper brittleness when heat treatment and cold plastic deformation is low, poor welding.

Mechanical properties
Blank sample size (mm): 25

Heat treatment:

The first quenching temperature (℃): 900; Coolant: Oil

Second quenching temperature (℃): -

Tempering heating temperature (℃): 600; coolant: water, oil

Tensile strength σb (MPa): ≥ 980 (100)

Yield strength σs (MPa): ≥ 835 (85)

Elongation δ5 (%): ≥ 12

Reduction of area ψ (%): ≥ 50

Impact energy Akv (J): ≥ 55

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

Brinell hardness (HBS100/3000) (annealing or tempering condition): ≦ 255