Steel 9310 · supply condition · default condition
Steel 9310-HR
Properties of the HR condition, compared with the other 9310 tempers.
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.
What is 9310-HR?
9310-HR is 9310 supplied in the HR 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. 9310-HR 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). 9310-HR 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).
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 — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
- Low electrical conductivity — 6.6 % IACS, worse than 77% of steel grades
- Difficult to machine — 40/100, worse than 76% of steel grades
9310-HR properties
Typical room-temperature values for 9310-HR — 9 properties are specific to this condition; the rest are grade-level values shared by every 9310 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
9310-HR 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).
Mechanical14
9310-HR 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-HR 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).
Electrical3
9310-HR conducts electricity at 6.6 % IACS, worse than 77% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of 9310-HR 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-HR's machinability is fair (40/100, worse than 76% of steel grades); weldability fair (35/100); 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.
Other 9310 tempers and conditions
9310 is also supplied in 6 other conditions. The full side-by-side table is on the 9310 overview.
- HRDefaultPick 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 MPa yield · 270 HB
- Q&TUse 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 MPa yield · 39 HRC
- CarburizedChoose 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 MPa yield · 60 HRC
- CDUse 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 MPa yield · 29 HRC
- NormalizedChoose 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 MPa yield · 269 HB
- AnnealedPick 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 MPa yield · 235 HB
Working with 9310-HR
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.
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.
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 | — |
9310-HR — frequently asked
What is 9310-HR used for?
9310-HR is typically used for helicopter gears, crankshafts and drive shafts. In short: heavy-duty case-hardening.
What is the yield strength of 9310-HR?
9310-HR 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-HR easy to machine?
Not especially — machinability is rated fair (40/100, worse than 76% 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-HR be welded?
With care — weldability is rated fair (35/100). 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-HR?
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-HR 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-HR?
9310-HR 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.
Can FabDigit make parts in 9310-HR?
Yes — 9310-HR is available for CNC machining and sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.