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E: enquiry@qilumetal.com
E: enquiry@qilumetal.com
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Grade: GB 12CrNi3
12CrNi3 is a carburizing alloy steel defined by its distinctive nickel‑chromium chemistry. The alloy contains 0.10–0.17% carbon for core ductility and 0.60–0.90% chromium to enhance hardenability and wear resistance. The standout element is nickel at 2.75–3.15% – significantly higher than conventional grades – which refines grain structure, boosts core toughness, and improves impact resistance even in large sections. Manganese (0.30–0.60%) and silicon (0.17–0.37%) serve as deoxidizers and strengtheners.
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12CrNi3
Qilu
GB 12CrNi3 is a high-grade carburizing alloy steel known for its superior hardenability, strength, and toughness compared to conventional grades such as 15Cr and 20Cr . This alloy steel incorporates nickel and chromium as primary alloying elements to deliver an exceptional combination of surface hardness and core toughness after heat treatment . The material is characterized by excellent low-temperature impact resistance, low notch sensitivity, and good machinability . It is widely utilized in demanding mechanical applications requiring high strength, wear resistance, and impact durability under heavy-load and high-speed conditions.
Grade | C | Si | Mn | P | S | Cr | Ni |
12CrNi3 | 0.10-0.17 | 0.17-0.37 | 0.30-0.60 | 0.030Max | 0.030Max | 0.60-0.90 | 2.75-3.15 |
| Property | Value (Min) |
| Tensile Strength | 930 MPa |
| Yield Strength | 685 MPa |
| Elongation at Break | 11% |
| Reduction of Area | 50% |
| Impact Toughness | 71 J |
| Hardness | 217Max HBW |
Quenching: First stage at 860°C, second stage at 780°C, followed by oil cooling .
Tempering: 200°C, followed by water or air cooling .
Carburizing: 900–920°C to achieve a uniform carburized layer with a gradual carbon gradient.
Note: The material is susceptible to temper brittleness and has a tendency to form white spots; process control is critical
Product type | Size range | Length |
Cold drawn bar | Φ3-Φ80mm | 6000-9000mm |
Hot rolled bar | Φ16-Φ310mm | 6000-9000mm |
Hot forged bar | Φ100-Φ1200mm | 3000-5800mm |
Hot rolled plate/sheet | T:3-200mm; W:1500-2500mm | 2000-5800mm |
Hot Forged block | T: 80-800mm; W: 100-2500mm | 2000-5800mm |
Surface Finish | Turned | Milled | Grinding(Best) | Polished(Best) | Peeled(Best) | Black Forged | Black Rolled |
Tolerance | +0/+3mm | +0/+3mm | +0/+0.05mm | +0/+0.05mm | +0/+0.1mm | +0/+5mm | +0/+1mm |
Straighness | 1mm/1000mm max. | 3mm/1000mm max. | |||||
12CrNi3 carburizing steel serves heavy machinery, automotive, aerospace, plastic mold, engineering equipment sectors:
Heavy-duty transmission gears, driving shafts, adjusting screws, camshafts, differential parts enduring high speed and cyclic impact loads.
High-load main spindles, piston rods, drive axles requiring ultra-high core toughness and surface wear resistance.
Cold extruded mold cavities, mold inserts; carburized surface achieves scratch resistance while core avoids cracking under clamping pressure.
Guide pins, gear sleeves, roller parts that need long service life under mixed impact & friction conditions.
12CrNi3 carries higher nickel content (2.75–3.15%) than 12CrNi2, delivering far stronger hardenability and superior low-temperature impact toughness.
12CrNi2 only fits thin cross-section small parts below 30mm, while 12CrNi3 supports workpieces up to 50mm thick without incomplete quenching.
12CrNi3 adopts double quenching (860°C + 780°C oil cooling), yet 12CrNi2 usually uses single quenching flow, leading to poorer dimensional stability after heat treatment.
For heavy cyclic impact loads, 12CrNi3 avoids brittle fracture much better than 12CrNi2.
Carbon content differs significantly: 12CrNi3 is low-carbon (0.10–0.17%) for carburizing service; 20CrNi3 has higher carbon (0.17–0.23%) and is mainly applied for quenching & tempering structural parts without carburization.
12CrNi3 surface can reach 58–62 HRC after carburizing, ideal for wear-resistant gears and molds. 20CrNi3 focuses on balanced core strength, with no obvious hard surface layer after heat treatment.
Standard tempering temperature of 12CrNi3 is 200°C low-temperature tempering; 20CrNi3 requires 480–530°C medium-temperature tempering to hit target yield strength.
Alloy element system is totally different: 12CrNi3 relies on Cr-Ni alloy to boost toughness and hardenability; 20CrMnTi uses Mn-Ti elements to refine grains and control heat treatment distortion.
12CrNi3 owns outstanding low-temperature performance, suitable for aerospace and cryogenic mechanical parts. 20CrMnTi works well under room-temperature automotive transmission loads but loses toughness sharply in cold environments.
20CrMnTi features smaller heat deformation for tiny precision gears; 12CrNi3 is the priority choice for medium-large heavy-load shafts and plastic mold blanks with thicker wall thickness.
A1: 12CrNi3 contains higher nickel content (2.75–3.15% vs lower Ni in 12CrNi2A), delivering much stronger hardenability. It is applicable to larger cross-section workpieces and owns better low-temperature impact toughness for heavier load conditions.
A2: As low-carbon carburizing steel with high alloy elements, welding is not recommended. Weld zones easily form brittle martensite and crack under load; use mechanical assembly instead of welding for structural connection.
A3: After standard gas carburizing + double quenching + low tempering, surface hardness reaches 58–62 HRC, core hardness remains 250–380 HBW to balance toughness and wear resistance.
A4: Yes. We offer fixed-length cutting, surface peeling, precision grinding, pre-annealing, pre-normalizing and finished quenched-tempered supply per customer technical drawings.
Contact us today for a quote or technical consultation on your specific application requirements.
