Steel 9310
AISI/SAE 9310 · UNS G93106 · EN 1.6657 · GB 20Cr2Ni4A
9310 (14NiCrMo13-4, 20Cr2Ni4A, 1.6657) is a low-carbon (about 0.10% C) 3.25Ni–1.2Cr–0.12Mo carburizing alloy steel developed for highly loaded gears, shafts and bearing races.
Values for the HR condition
9310 tempers and conditions
9310 is supplied in 7 conditions, soft to hard. HR 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 |
|---|---|---|---|---|---|---|
( 630 °C / ) | Pick the subcritical/spheroidize anneal near 630 °C as the standard machining blank: lowest hardness at 235 HB, best cutting and cold forming before carburizing and quenching. | 450 | 820 | 17 | 235 HB | — |
( 890 °C ) + | Choose normalizing near 890 °C with air cooling plus a high-temperature temper for uniform structure and high toughness in rough machining; a common AMS 6265 bar supply state. | 570 | 910 | 19 | 269 HB | — |
HRDefault Hot rolled | Pick hot-rolled bar as the lowest-cost stock form; with no post-rolling heat treatment hardness and structure are uneven, so normalize or anneal before machining. | 600 | 950 | 15 | 27 HRC | 6.6 % IACS |
Cold rolled | Choose annealed, skin-passed cold-rolled sheet or strip (limited availability) as stamping blanks for thin-wall carburized parts, shims and retaining-clip type components. | 640 | 880 | 13 | 25 HRC | 6.6 % IACS |
Cold drawn | Use cold-drawn bright bar for direct turning of small pinions and shafts where tight diameter tolerance, straightness and surface finish matter; elongation falls to 11%. | 810 | 1,000 | 11 | 29 HRC | — |
+ 58–62 HRC / 32–40 HRC | Choose the final service condition — carburized, quenched and tempered to a 58–62 HRC case over a 32–40 HRC core — for aerospace and helicopter gears; machine before treatment. | 1,030 | 1,240 | 15 | 60 HRC | — |
Quenched and tempered | Use direct oil quenching from about 843 °C plus a low or medium temper, with no carburizing, for shafts needing 1300 MPa tensile and toughness but no hard wear surface. | 1,100 | 1,300 | 14 | 39 HRC | — |
What is 9310?
9310 (14NiCrMo13-4, 20Cr2Ni4A, 1.6657) is a low-carbon (about 0.10% C) 3.25Ni–1.2Cr–0.12Mo carburizing alloy steel developed for highly loaded gears, shafts and bearing races. After carburizing and quenching the case reaches 58–62 HRC while the high-nickel core keeps high toughness and low-temperature impact strength; vacuum-remelted aircraft-quality material to AMS 6265/6267 is used for helicopter and aero-engine transmission gears. Limits are high cost, a mandatory carburize-quench-temper cycle, corrosion resistance no better than plain alloy steel (plating or oiling required), and welding that needs preheat plus post-weld heat treatment. 9310 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). 9310 has a yield strength of 600 MPa (87 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 77% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi).
What is 9310 used for?
- Helicopter gears
- Crankshafts
- Drive shafts
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
- High strength — 600 MPa (87 ksi), better than 77% of steel grades
Limitations
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% 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
- Low electrical conductivity — 6.6 % IACS, worse than 76% of steel grades
9310 properties
Typical room-temperature values for 9310-HR; bars are the position among steel grades.
Physical3
9310 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).
Mechanical17
9310 has a yield strength of 600 MPa (87 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 77% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
9310 is rated for continuous service to 400°C (752 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
9310 conducts electricity at 6.6 % IACS, worse than 76% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of 9310 takes about 34 MJ of energy and emits 2.5 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
9310's machinability is fair (40/100, worse than 77% of steel grades); weldability fair (38/100); formability fair (35/100).
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. 9310 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 9310
Is 9310 easy to machine?
Machinability in the annealed or normalized condition is moderate (about 45% of 1212): use coated carbide, moderate cutting speeds and generous coolant, and leave grinding stock on gear teeth. After carburizing and quenching, finish only by grinding or EDM.
Can 9310 be welded?
Weldable but highly hardenable: preheat 150–260 °C, use low-hydrogen or matching Ni-Cr-Mo filler, and temper or stress relieve immediately after welding. Do not weld in carburized areas.
Can 9310 be formed, bent or molded?
Hot forge in the annealed condition at 1100–1200 °C, finish forging above 900 °C and cool slowly; cold forming is moderate with bend radii of at least 3t, followed by stress-relief annealing.
Manufacturability
The process limits FabDigit applies to 9310. Every 9310 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better40 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair35 / 100 |
|---|---|
| Weldability | Better38 / 100 |
9310 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 – 0.65 | 0.55 |
| SiAMS 6265 usually limits to 0.20-0.35 | 0.15 – 0.35 | 0.25 |
| Ni | 3 – 3.5 | 3.25 |
| Cr | 1 – 1.4 | 1.2 |
| Mo | 0.08 – 0.15 | 0.12 |
| Paerospace grade AMS 6265 ≤ 0.010 | ≤ 0.03 | |
| Saerospace grade AMS 6265 ≤ 0.010 | ≤ 0.03 | |
| Curesidual element | ≤ 0.35 | |
| Fe | balance |
What surface finishes work on 9310?
Not anodizable. After carburizing and grinding use phosphate, black oxide, cadmium or zinc-nickel plating, or shot peening to raise bending fatigue life; bake after electroplating to remove hydrogen.
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 9310 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G93106
- EN / DIN / Werkstoff-Nr.
- 1.6657
- GB (China)
- 20Cr2Ni4A
- Similar grades
- 14NiCrMo13-4
How much does 9310 cost?
9310 is a premium-cost steel ($$$), cheaper than about 60% 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.
9310 — frequently asked
What is 9310 used for?
9310 is typically used for helicopter gears, crankshafts and drive shafts. In short: heavy-duty case-hardening.
What is the yield strength of 9310?
9310 has a typical yield strength of 600 MPa (87 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 77% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 9310 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machinability in the annealed or normalized condition is moderate (about 45% of 1212): use coated carbide, moderate cutting speeds and generous coolant, and leave grinding stock on gear teeth. After carburizing and quenching, finish only by grinding or EDM.
Can 9310 be welded?
With care — weldability is rated fair (38/100). Weldable but highly hardenable: preheat 150–260 °C, use low-hydrogen or matching Ni-Cr-Mo filler, and temper or stress relieve immediately after welding. Do not weld in carburized areas.
What surface finishes work on 9310?
Not anodizable. After carburizing and grinding use phosphate, black oxide, cadmium or zinc-nickel plating, or shot peening to raise bending fatigue life; bake after electroplating to remove hydrogen.
Can 9310 be formed, bent or molded?
Hot forge in the annealed condition at 1100–1200 °C, finish forging above 900 °C and cool slowly; cold forming is moderate with bend radii of at least 3t, followed by stress-relief annealing.
What is the maximum service temperature of 9310?
9310 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 9310-HR and 9310-CD?
HR is the default condition — pick hot-rolled bar as the lowest-cost stock form; with no post-rolling heat treatment hardness and structure are uneven, so normalize or anneal before machining. CD: use cold-drawn bright bar for direct turning of small pinions and shafts where tight diameter tolerance, straightness and surface finish matter; elongation falls to 11%. Yield strength is 600 MPa in HR versus 810 MPa in CD.
How much does 9310 cost?
9310 is a premium-cost steel ($$$), cheaper than about 60% 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.
Can FabDigit make parts in 9310?
Yes — 9310 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- AMS 6265 — Steel Bars, Forgings, Tubing 3.2Ni-1.2Cr-0.12Mo (0.07-0.13C), Vacuum Consumable Electrode Remelted — SAE International (2020)
- AMS 6260 — Steel Bars, Forgings and Tubing 3.2Ni-1.2Cr-0.12Mo, Carburizing Grade — SAE International (2019)
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- EN 10084 — Case hardening steels (14NiCrMo13-4, 1.6657) — CEN (2008)
- GB/T 3077 — (12Cr2Ni4A ) — SAC (2015)
- 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)
- MMPDS-17 low-alloy steel typical property tables — Battelle/FAA (2022)
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.