12CrNi3A steel belongs to alloy carburized steel. It has higher hardenability than 12CrNi2A steel. So, it can be used to manufacture parts with a larger section than 12CrNi2A steel. The steel has good comprehensive mechanical properties after quenching and low or high-temperature tempering. The steel has good low-temperature toughness. Small notch sensitivity. Good cutting performance.


12CrNi3A Worldwide equivalents


12CrNi3A Steel Chemical Composition


The critical temperature of 12CrNi3A Steel

Critical pointAc1Ac3Ar1Ar3Ms

Mechanical Properties of 12CrNi3A Steel

  • Tensile strength σb (MPa): ≥930 (95)
  • Yield strength σs (MPa): ≥685 (70)
  • Elongation δ5 (%): ≥11
  • Reduction of ψ (%): ≥50
  • Impact energy Akv (J): ≥71
  • Impact toughness αkv (J / cm2): ≥88 (9)
  • Hardness: ≤217HB

Heat treatment


Temperature: 870 ~ 900 ℃ (890 ℃ recommended)

Cooling mode: reduce cooling with the furnace

Hardness (HBW): 156 ~ 229


Temperature: 885 ~ 940 ℃, cooling mode: cooling in air


Temperature: 860 ℃, cooling mode: cooling in oil, hardness (HRC): ≥ 43


Temperature/℃Cooling modeHardness(HRC)
650-680(High temperature tempering)Air/
520-580Oil or water20-30
420-480Oil or water30-70
400-500Oil or water31-39
150-400Oil or water39-43

Features and Applications

It is a high-grade carburizing steel with a wide range of uses. Compared with 15Cr and 20Cr steel, its strength, plasticity and hardenability are high.

It is mainly used to make spindles that need high strength, high hardness and high toughness under heavy load conditions.

It requires high center toughness or shafts and rods that can withstand impact loads, surface wear resistance, and small heat treatment deformation.

Work under high speed and impact loads Various transmission gears, adjusting screws, camshafts.

Available Size

Round BarDiameter(mm): 6-800mm ,Length: 1000-9000mm or custom size
Plate/Flat/BlockThickness: 6mm-500mm , Width: 20mm-1000mm or custom size
Tolerance±1%,Thickness: +/-0.02mm, Width:+/-2mm