Steel 20Cr2Ni4
20Cr2Ni4 is a high-alloy Cr-Ni case-hardening steel comparable to SAE 9310, offering deep hardenability and a high-toughness core for heavily loaded gearing.
Reference datasheet — 20Cr2Ni4 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 A condition
20Cr2Ni4 tempers and conditions
20Cr2Ni4 is supplied in 7 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stock condition for bar and forgings: soft enough to rough-machine gear blanks before carburizing. | 680 | 880 | 16 | 22 HRC | — |
Normalized and tempered | Normalize ~890 °C then temper 630–670 °C to break up the air-hardened structure and stabilise machining before carburizing. | 750 | 950 | 15 | 26 HRC | — |
Hot rolled | Cheapest mill condition; this steel air-hardens, so hot-rolled bar is hard and must be softened before machining. | 800 | 1,100 | 12 | 34 HRC | 6.6 % IACS |
Cold drawn | Small-diameter bright bar for shafts and pins where a close-tolerance blank is wanted before case hardening. | 800 | 950 | 11 | 28 HRC | 6.6 % IACS |
quenched and tempered to a machinable core hardness | Tempered high (≈550–600 °C) for large shafts, gear blanks and nitriding bases needing toughness plus good machinability. | 860 | 1,000 | 16 | 32 HRC | — |
Carburized, hardened and low tempered | The service condition for gears: gas-carburize 920–930 °C, double quench (or direct quench + sub-zero), temper 160–200 °C for maximum contact and bending fatigue strength. | 1,080 | 1,250 | 11 | 61 HRC | — |
Double quenched (880 °C + 780 °C oil) and tempered 200 °C | The standard's property-qualification condition; also used for through-hardened high-strength shafts and fasteners. | 1,130 | 1,250 | 12 | 40 HRC | — |
What is 20Cr2Ni4?
20Cr2Ni4 is a high-alloy Cr-Ni case-hardening steel comparable to SAE 9310, offering deep hardenability and a high-toughness core for heavily loaded gearing. It is specified for aerospace and heavy industrial gears and comes as annealed, hot-rolled, normalized-and-tempered and cold-drawn bar and forgings; default-condition core values are about 680 MPa yield, 880 MPa tensile, 16% elongation and 240 HB (22 HRC), with service to roughly 400 °C. Cost, availability, machinability (score 42) and low cold formability are the trade-offs; 20CrNiMo (8620) covers less demanding gears. 20Cr2Ni4 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). 20Cr2Ni4 has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 80% of steel grades. Elongation at break is 16% and the elastic modulus is 207 GPa (30 Msi).
What is 20Cr2Ni4 used for?
- Aircraft transmission gears
- Helicopter and rotorcraft gearbox gears
- Heavy-duty industrial gearboxes
- Accessory drive gears
- High-load pinions and ring gears
- Marine reduction gears
- Splined power-transmission shafts
Advantages
- High strength — 680 MPa (98.6 ksi), better than 80% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- High embodied carbon — 2.7 kg CO₂/kg, worse than 89% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
20Cr2Ni4 properties
Typical room-temperature values for 20Cr2Ni4-A; bars are the position among steel grades.
Physical3
20Cr2Ni4 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
20Cr2Ni4 has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 80% of steel grades. Elongation at break is 16% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
20Cr2Ni4 is rated for continuous service to 400°C (752 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical2
20Cr2Ni4 has an electrical resistivity of 2.6×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 20Cr2Ni4 takes about 36 MJ of energy and emits 2.7 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 30%.
Manufacturability7
20Cr2Ni4's machinability is fair (42/100, worse than 73% of steel grades); weldability poor (30/100); formability fair (40/100).
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. 20Cr2Ni4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 20Cr2Ni4
Is 20Cr2Ni4 easy to machine?
Machine only after normalize + high temper or full anneal (≤269 HB); the high-Ni matrix work-hardens and smears, so use rigid setups, positive-rake coated carbide, moderate speed and heavy coolant, and leave 0.2–0.4 mm grinding stock for post-carburizing distortion.
Can 20Cr2Ni4 be welded?
Low carbon makes it weldable but the alloy is air-hardening: preheat 200–300 °C, use low-hydrogen consumables, keep interpass heat, and stress-relieve/temper afterwards; never weld carburized or hardened parts.
Can 20Cr2Ni4 be formed, bent or molded?
Forge at 1150–1200 °C down to about 850 °C followed by controlled slow cooling plus anneal; cold forming is limited to light straightening and thread rolling in the softened condition.
20Cr2Ni4 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 | 0.17 – 0.23 | 0.2 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.3 – 0.6 | 0.45 |
| Cr | 1.25 – 1.65 | 1.45 |
| Ni | 3.25 – 3.75 | 3.5 |
| P≤0.025 for high-quality 'A' grade (20Cr2Ni4A) | ≤ 0.03 | |
| S≤0.025 for high-quality 'A' grade | ≤ 0.03 | |
| Curesidual | ≤ 0.25 | |
| Moresidual only; SAE 9310 by contrast specifies 0.08–0.15 Mo | ≤ 0.15 | |
| Fe | balance |
What surface finishes work on 20Cr2Ni4?
Case-hardened surfaces are finish-ground and optionally shot-peened or superfinished for fatigue life; unhardened areas need phosphate, black oxide, Zn/Ni plating or oil since the steel has no corrosion resistance (bake after plating to avoid hydrogen embrittlement).
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 20Cr2Ni4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 9310
How much does 20Cr2Ni4 cost?
20Cr2Ni4 is a standard-cost steel ($$), cheaper than about 71% 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.
20Cr2Ni4 — frequently asked
What is 20Cr2Ni4 used for?
20Cr2Ni4 is typically used for aircraft transmission gears, helicopter and rotorcraft gearbox gears, heavy-duty industrial gearboxes, accessory drive gears, high-load pinions and ring gears and marine reduction gears. In short: 9310-class aerospace gear steel; deepest hardenability, highest cost; toughest core in family.
What is the yield strength of 20Cr2Ni4?
20Cr2Ni4 has a typical yield strength of 680 MPa (98.6 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 20Cr2Ni4 easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine only after normalize + high temper or full anneal (≤269 HB); the high-Ni matrix work-hardens and smears, so use rigid setups, positive-rake coated carbide, moderate speed and heavy coolant, and leave 0.2–0.4 mm grinding stock for post-carburizing distortion.
Can 20Cr2Ni4 be welded?
Not readily — weldability is rated poor (30/100). Low carbon makes it weldable but the alloy is air-hardening: preheat 200–300 °C, use low-hydrogen consumables, keep interpass heat, and stress-relieve/temper afterwards; never weld carburized or hardened parts.
What surface finishes work on 20Cr2Ni4?
Case-hardened surfaces are finish-ground and optionally shot-peened or superfinished for fatigue life; unhardened areas need phosphate, black oxide, Zn/Ni plating or oil since the steel has no corrosion resistance (bake after plating to avoid hydrogen embrittlement).
Can 20Cr2Ni4 be formed, bent or molded?
Forge at 1150–1200 °C down to about 850 °C followed by controlled slow cooling plus anneal; cold forming is limited to light straightening and thread rolling in the softened condition.
What is the maximum service temperature of 20Cr2Ni4?
20Cr2Ni4 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20Cr2Ni4-A and 20Cr2Ni4-QT200?
A is the default condition — standard stock condition for bar and forgings: soft enough to rough-machine gear blanks before carburizing. QT200: the standard's property-qualification condition; also used for through-hardened high-strength shafts and fasteners. Yield strength is 680 MPa in A versus 1,130 MPa in QT200.
How much does 20Cr2Ni4 cost?
20Cr2Ni4 is a standard-cost steel ($$), cheaper than about 71% 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 / AMS 6265 (9310 carburizing steel) — SAE International (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4A — Steel Heat Treating Fundamentals and Processes (carburizing) — ASM International (2013)
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.