1.Basic Information and Classification
12Х2Н4А is a Russian grade of alloy structural steel (corresponding to the Chinese grade 12cr2ni4A , classified as a high-strength carburizing steel. Due to its chromium (Х) and nickel (Н) alloy elements, it combines high strength, good toughness, and wear resistance. It is primarily used for manufacturing precision parts subjected to high loads.
2 . Chemical composition
Elements C Si Mn Cr Ni P≤ S≤
Content 0.10-0.16 0.17-0.37 0.30-0.60 1.25-1.65 3.25-3.65 0.030 0.030
Key element functions:
Carbon (C): Ensures hardness and strength after quenching;
Chromium (Cr): Improves corrosion resistance, wear resistance, and hardenability;
Nickel (Ni): Enhances toughness, plasticity, and low-temperature performance, and improves hardenability.
3. Mechanical properties (after heat treatment)
performance Values (standard conditions)
tensile strength σb（MPa） ≥1175
yield strength σs（MPa） ≥1080
Elongation δ5（%） ≥10
Cross-sectional shrinkage rate ψ（%） ≥45
Hardness （HB） 269-321
Feature: After carburizing + quenching + tempering treatment, it achieves high surface hardness (HRC 58-62) combined with excellent core toughness, making it particularly suitable for components subjected to alternating loads and impact loads.
4.Heat Treatment Process
Carburizing Treatment:
Temperature: 900–920°C
Duration: 8–10 hours (for case depth of 1–1.5 mm)
Medium: Solid carburizer or gas (e.g., methane).
Quenching:
First Quenching: 860°C oil quenching (refines grain structure).
Second Quenching: 780–800°C oil quenching (enhances surface hardness).
Tempering:
Temperature: 150–200°C (low-temperature tempering)
Purpose: Relieves residual stresses while retaining high hardness (HRC 58+).
5. Application Field
Aerospace: Aircraft landing gear, engine gears, high-strength bolts.
Machinery Manufacturing: Automotive transmission gears, heavy-duty lathe spindles, wear-resistant mining equipment parts.
Defense Industry: Projectile casings, high-load bearing races.
Mold Manufacturing: Cold-work molds requiring exceptional wear resistance and toughness.
6. Machining & Welding Properties
Machinability
Good machinability in annealed condition.
Post-carburizing/quenching requires carbide tools or grinding (due to high surface hardness).
Weldability
Poor weldability: High nickel content increases crack susceptibility.
Protocol: Preheating (200–300°C) + post-weld slow cooling + low-hydrogen electrodes (e.g., E5015).
Forging Performance
Start: 1,150–1,200°C
Finish: ≥850°C
Post-forging: Slow cooling to prevent cracking.
7. Corrosion & Oxidation Resistance
Corrosion Resistance: Superior to carbon steel in atmosphere/fresh water/weakly corrosive media (due to Cr/Ni).
Not stainless: Requires coatings (e.g., plating/painting) in acidic/salt-spray environments.
Oxidation Resistance: Stable below 300°C; degrades above.
Max service temperature: 400°C (short-term).
8. Approxmate Equivelent Standards
Country Standard Equivalent Grade
Russia (GOST) 4543-71 12Х2Н4А
China (GB) GB/T 3077 12Cr2Ni4A
USA (ASTM) – 2515
Europe (EN) – 1.6529
Available Forms: Round bars, forged blocks, hot/cold-rolled strips, calibrated rods (per GOST 1051/7417/8559)
9.Market & Supply Status
Leading Producers:
Russia: Novolipetsk Steel (NLMK), Magnitogorsk Iron & Steel Works (MMK)
China: domestic alternatives ( 12Cr2Ni4A).
Cost characteristics: Due to its high nickel alloy content, it is more expensive than
ordinary carbon steel, approximately 3-5 times the price of 45# steel, and is suitable for high-end applications.
10.Supply & Service Commitment
12Х2Н4А delivers unparalleled core toughness, carburized surface hardness, and fatigue resistance, establishing it as the essential material for critical rotating components across aerospace, automotive, and heavy industries.
Looking to specify or stock 12Х2Н4А? We offer GOST compliant 12Х2Н4А bars, forgings, and strips with various choice—cut to size and heat-treated according to your requirements.
Custom-processed with:
✓ Precision cut-to-size.
✓ Tailored heat treatment (to your specifications).
Trade term:
✓Currency in RMB based on FOB,CIF,DDU,EXW.
✓We have VTB bank to receive RMB from Russia.
Stability:
✓We main a stable supply chain for the Russian marekt , 60 tons of stainless steel products to Russian last month ,it’s a municipal infrastructure projec, and it’s continous.
Contact us for quotes and material test reports by aurora@hnyasco.com , we will offer our best price with a prompt delivery.