Steel 3310
AISI/SAE 3310 · UNS G33100
3310 is a high-nickel carburizing steel (UNS G33100) selected for very high core toughness, historically the standard for aerospace gearing.
Reference datasheet — 3310 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 Annealed condition
3310 tempers and conditions
3310 is supplied in 9 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
- Spheroidize Annealed
- Annealed
- Normalized+Tempered
- Hot Rolled
- Normalized
- Cold Drawn
- Q&T 30-36 HRC (core, uncarburized)
- Carburized 58-62 HRC (double quench)
- Carburized 58-62 HRC (single quench)
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
optimized for machining and cold work | Choose when heavy hobbing, broaching or cold heading of the blank is required before carburizing. | 400 | 620 | 28 | 170 HB | 5.7 % IACS |
AnnealedDefault full anneal, bar/forging stock for carburizing | Standard stocking condition: softest, most machinable state for rough-cutting gear blanks before carburizing. | 425 | 665 | 26 | 187 HB | — |
Normalized and tempered | Preferred pre-carburizing condition for large forgings: refined grain plus softening temper for cutting. | 480 | 720 | 24 | 17 HRC | 5.7 % IACS |
as-rolled bar | Lowest-cost mill condition; usually re-annealed or normalized before machining because as-rolled hardness is variable. | 520 | 780 | 20 | 21 HRC | 5.7 % IACS |
900–925 °C air cool | Grain refinement / structure homogenization of forgings; note the high Ni-Cr content makes this grade air-hardening, so normalized hardness is high. | 560 | 830 | 20 | 24 HRC | 5.6 % IACS |
Cold drawn (annealed and cold finished) bar | Use for small-diameter shafts and pins needing close tolerance and better surface before carburizing. | 650 | 760 | 14 | 20 HRC | 5.7 % IACS |
Direct hardened and tempered | For non-wearing structural parts (shafts, links) that need very high toughness at moderate strength without a hard case. | 790 | 1,050 | 17 | 33 HRC | — |
Carburized, double quenched and tempered | The service condition for aerospace gears and bearing races: hard wear-resistant case over a very tough low-carbon martensitic core. | 860 | 1,170 | 15 | 60 HRC | — |
Carburized, single quenched and tempered | Lower-cost route with less distortion than double quench; slightly coarser case structure and marginally lower core toughness. | 900 | 1,240 | 13 | 60 HRC | — |
What is 3310?
3310 is a high-nickel carburizing steel (UNS G33100) selected for very high core toughness, historically the standard for aerospace gearing. It is carburized to a 58-62 HRC case by single or double quench over a core quenched and tempered to 30-36 HRC, and is available as hot-rolled, cold-drawn, annealed, spheroidize-annealed, normalized and normalized-plus-tempered bar. Default properties are 425 MPa yield, 665 MPa tensile, 26% elongation and 187 HB. The limits are cost and availability, a machinability rating of only 40 and poor weldability because the alloy air-hardens; 9310 is the usual modern substitute. 3310 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). 3310 has a yield strength of 425 MPa (61.6 ksi) and a tensile strength of 665 MPa (96.5 ksi) — weaker than 52% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
What is 3310 used for?
- Aircraft gearbox gears
- High-toughness shafts
- Helicopter transmission pinions
- Bearing races
- Splined couplings
- Heavy-duty gear sets
Advantages
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
3310 properties
Typical room-temperature values for 3310-Annealed; bars are the position among steel grades.
Physical3
3310 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).
Mechanical13
3310 has a yield strength of 425 MPa (61.6 ksi) and a tensile strength of 665 MPa (96.5 ksi) — weaker than 52% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
3310 is rated for continuous service to 200°C (392 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical2
3310 has an electrical resistivity of 3×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of 3310 takes about 36 MJ of energy and emits 2.6 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 25%.
Manufacturability7
3310's machinability is fair (40/100, worse than 77% of steel grades); weldability poor (25/100); formability fair (45/100).
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. 3310 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 3310
Is 3310 easy to machine?
Machine in the annealed/spheroidized state with sharp carbide tooling and rigid setups; the high-Ni matrix is gummy and work-hardens, so use positive rake, generous feed and flood coolant, and finish-grind after carburizing.
Can 3310 be welded?
Poor weldability — the alloy air-hardens; if welding is unavoidable use low-hydrogen or matching filler, 250–300 °C preheat, low interpass restraint and immediate post-weld temper, and never weld carburized surfaces.
Can 3310 be formed, bent or molded?
Hot forge at 1100–1200 °C, finish above 950 °C and slow-cool or normalize plus temper; cold forming is limited to mild bends/heading in the annealed condition.
3310 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 | 0.08 – 0.13 | 0.1 |
| Mn | 0.45 – 0.6 | 0.52 |
| Si | 0.2 – 0.35 | 0.27 |
| Niprimary source of core toughness and hardenability | 3.25 – 3.75 | 3.5 |
| Cr | 1.4 – 1.75 | 1.57 |
| P0.015 max for electric-furnace E3310 | ≤ 0.03 | |
| S0.015 max for electric-furnace E3310 | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on 3310?
No corrosion resistance of its own: after tempering apply black oxide, manganese phosphate, or cadmium/zinc-nickel plate with hydrogen-embrittlement bake; case-carburized surfaces are typically hard-ground and honed.
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 3310 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G33100
How much does 3310 cost?
3310 is a premium-cost steel ($$$), cheaper than about 51% 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.
3310 — frequently asked
What is 3310 used for?
3310 is typically used for aircraft gearbox gears, high-toughness shafts, helicopter transmission pinions, bearing races, splined couplings and heavy-duty gear sets. In short: highest core toughness; aerospace gear heritage; hardest of family to machine.
What is the yield strength of 3310?
3310 has a typical yield strength of 425 MPa (61.6 ksi) and a tensile strength of 665 MPa (96.5 ksi) — weaker than 52% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 3310 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machine in the annealed/spheroidized state with sharp carbide tooling and rigid setups; the high-Ni matrix is gummy and work-hardens, so use positive rake, generous feed and flood coolant, and finish-grind after carburizing.
Can 3310 be welded?
Not readily — weldability is rated poor (25/100). Poor weldability — the alloy air-hardens; if welding is unavoidable use low-hydrogen or matching filler, 250–300 °C preheat, low interpass restraint and immediate post-weld temper, and never weld carburized surfaces.
What surface finishes work on 3310?
No corrosion resistance of its own: after tempering apply black oxide, manganese phosphate, or cadmium/zinc-nickel plate with hydrogen-embrittlement bake; case-carburized surfaces are typically hard-ground and honed.
Can 3310 be formed, bent or molded?
Hot forge at 1100–1200 °C, finish above 950 °C and slow-cool or normalize plus temper; cold forming is limited to mild bends/heading in the annealed condition.
What is the maximum service temperature of 3310?
3310 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.
How much does 3310 cost?
3310 is a premium-cost steel ($$$), cheaper than about 51% 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 — SAE International (2021)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- 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)
- ASM Handbook Vol. 16 — Machining (machinability ratings) — ASM International (1989)
- GB/T 3077 — (12Cr2Ni4A ) — SAC / (2015)
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.