Steel 12CrNi3A
EN 12CrNi3A
12CrNi3A (equivalent to AISI 3310) is a chromium-nickel carburizing steel with roughly 3 % Ni for core toughness and moderate hardenability, sitting in the EN 10084 case-hardening family.
Reference datasheet — 12CrNi3A is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the QT condition
12CrNi3A tempers and conditions
12CrNi3A is supplied in 8 conditions, soft to hard. QT is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Pick for maximum machinability and cold workability before carburizing; the standard stocked bar condition under GB/T 3077. | 390 | 620 | 22 | 190 HB | — |
Normalized + high-temperature temper | Common mill delivery route for Ni-Cr carburizing bar: gives uniform, easily machined structure with ≤269 HBW. | 450 | 680 | 20 | 14 HRC | 5.9 % IACS |
Hot rolled | Raw mill condition of round bar; usually re-annealed or normalized before machining because as-rolled Ni-Cr steel is already fairly hard. | 500 | 780 | 16 | 21 HRC | 6.2 % IACS |
Normalized | Grain refinement and structure homogenisation before carburizing or final Q&T; harder than annealed. | 540 | 800 | 18 | 22 HRC | 6.2 % IACS |
Cold drawn | Choose for close-tolerance bright bar and small carburized pins/shafts machined with minimal stock removal. | 640 | 780 | 10 | 20 HRC | 6 % IACS |
Quenched and high-temperature tempered ~600 °C | Use when maximum core toughness and dimensional stability matter more than hardness, e.g. un-carburized heavy shafts. | 700 | 850 | 17 | 25 HRC | — |
QTDefault Quenched and tempered | Standard property-verification condition of GB/T 3077 and the usual through-hardened state for un-carburized shafts and fasteners in this grade. | 785 | 980 | 13 | 31 HRC | — |
Carburized + hardened + 180–200 °C temper | The service condition for gears and pins: 0.6–1.5 mm hard wear-resistant case over a tough ~3%Ni core. | 800 | 1,050 | 11 | 60 HRC | — |
What is 12CrNi3A?
12CrNi3A (equivalent to AISI 3310) is a chromium-nickel carburizing steel with roughly 3 % Ni for core toughness and moderate hardenability, sitting in the EN 10084 case-hardening family. It is used for medium-duty carburized gears, shafts and pins, and is stocked hot-rolled, annealed, normalized, cold-drawn, quenched-and-tempered and carburized as bar and forgings. Typical hardened-and-tempered properties are 785 MPa yield, 980 MPa tensile, 13 % elongation and 300 HB (31 HRC), with service to 200 °C. The nickel-rich matrix machines gummy and welding needs preheat; 20Cr2Ni4A is the choice for heavier, more highly loaded sections. 12CrNi3A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). 12CrNi3A has a yield strength of 785 MPa (114 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
What is 12CrNi3A used for?
- gear shafts
- carburized pins
- small gears
Advantages
- High strength — 785 MPa (114 ksi), better than 86% of steel grades
- Polishes to a fine finish — 68/100, better than 83% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Low electrical conductivity — 5.7 % IACS, worse than 80% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
12CrNi3A properties
Typical room-temperature values for 12CrNi3A-QT; bars are the position among steel grades.
Physical3
12CrNi3A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
12CrNi3A has a yield strength of 785 MPa (114 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
12CrNi3A is rated for continuous service to 200°C (392 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
12CrNi3A conducts electricity at 5.7 % IACS, worse than 80% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of 12CrNi3A takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
12CrNi3A's machinability is fair (40/100, worse than 77% of steel grades); weldability fair (35/100); formability poor (22/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 12CrNi3A is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 12CrNi3A
Is 12CrNi3A easy to machine?
Machine in the annealed or high-temper condition (≤269 HBW); the 3%Ni matrix is gummy, so use sharp positive-rake carbide, rigid setups and generous coolant, and finish-grind after carburizing.
Can 12CrNi3A be welded?
Weldable with low-hydrogen consumables but requires 150–250 °C preheat and prompt stress relief/tempering; never weld a carburized surface.
Can 12CrNi3A be formed, bent or molded?
Hot forge at 1150–850 °C followed by slow cooling and normalizing; cold forming only in the annealed state and limited to modest deformation.
12CrNi3A chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.1 – 0.17 | 0.13 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.3 – 0.6 | 0.45 |
| Cr | 0.6 – 0.9 | 0.75 |
| Ni | 2.75 – 3.25 | 3 |
| Curesidual | ≤ 0.25 | |
| Phigh-grade quality (A) limit | ≤ 0.03 | |
| Shigh-grade quality (A) limit | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on 12CrNi3A?
Not anodizable — protect with oil, phosphate/black oxide, zinc or nickel plating; masking with copper plate or paste is standard for selectively carburized areas.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 12CrNi3A in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 3310
How much does 12CrNi3A cost?
12CrNi3A is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
12CrNi3A — frequently asked
What is 12CrNi3A used for?
12CrNi3A is typically used for gear shafts, carburized pins and small gears. In short: medium-duty carburizing steel; tough 3 % Ni core; lighter-duty 9310 alternative.
What is the yield strength of 12CrNi3A?
12CrNi3A has a typical yield strength of 785 MPa (114 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 12CrNi3A easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machine in the annealed or high-temper condition (≤269 HBW); the 3%Ni matrix is gummy, so use sharp positive-rake carbide, rigid setups and generous coolant, and finish-grind after carburizing.
Can 12CrNi3A be welded?
With care — weldability is rated fair (35/100). Weldable with low-hydrogen consumables but requires 150–250 °C preheat and prompt stress relief/tempering; never weld a carburized surface.
What surface finishes work on 12CrNi3A?
Not anodizable — protect with oil, phosphate/black oxide, zinc or nickel plating; masking with copper plate or paste is standard for selectively carburized areas.
Can 12CrNi3A be formed, bent or molded?
Hot forge at 1150–850 °C followed by slow cooling and normalizing; cold forming only in the annealed state and limited to modest deformation.
What is the maximum service temperature of 12CrNi3A?
12CrNi3A is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 12CrNi3A-QT and 12CrNi3A-A?
QT is the default condition — standard property-verification condition of GB/T 3077 and the usual through-hardened state for un-carburized shafts and fasteners in this grade. A: pick for maximum machinability and cold workability before carburizing; the standard stocked bar condition under GB/T 3077. Yield strength is 785 MPa in QT versus 390 MPa in A.
How much does 12CrNi3A cost?
12CrNi3A is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- SAE J404 Chemical Compositions of SAE Alloy Steels (3310 comparison) — SAE International (2009)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing of Ni-Cr steels) — ASM International (1991)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.