Steel AerMet 310-ANN (Annealed)
Heat-treated state
Mill-supplied soft condition (~40 HRC max) for rough machining before final heat treatment.
Values for the ANN condition
Other AerMet 310 tempers and conditions
AerMet 310 is listed in 6 conditions; see the grade overview at AerMet 310.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page Annealed | Mill-supplied soft condition (~40 HRC max) for rough machining before final heat treatment. | 1,030 | 1,280 | 15 | 39 HRC | — |
Normalized | Intermediate homogenizing/grain-refining step before annealing or hardening; not a delivery condition for finished parts. | 1,270 | 1,650 | 11 | 50 HRC | 2.5 % IACS |
As-quenched + cryogenic | Transient condition after 885 °C austenitize, oil quench and −73 °C cryogenic soak; must be aged before service. | 1,480 | 1,900 | 8 | 55 HRC | 2.4 % IACS |
Hardened + aged 496 °C (925 °F) 5 h | Slightly overaged for higher fracture toughness and ductility where damage tolerance governs. | 1,860 | 2,070 | 11 | 55 HRC | 2.7 % IACS |
A900Default Hardened + aged 482 °C (900 °F) 5 h, air cool | Standard aerospace heat treatment giving the nominal ~310 ksi strength with usable K_IC — the design condition for landing gear and structural parts. | 1,960 | 2,140 | 10 | 57 HRC | — |
Hardened + aged 468 °C (875 °F) 5 h | Choose when maximum tensile/yield strength is required and fracture toughness demand is moderate. | 2,000 | 2,210 | 9 | 58 HRC | 2.7 % IACS |
What is AerMet 310-ANN?
AerMet 310-ANN is AerMet 310 heat treated to ANN — mill-supplied soft condition (~40 HRC max) for rough machining before final heat treatment. AerMet 310-ANN has a yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,280 MPa (186 ksi) — stronger than 93% of steel grades. Elongation at break is 15% and the elastic modulus is 194 GPa (28.1 Msi). AerMet 310-ANN has a density of 8 g/cm³ (0.289 lb/in³), heavier than 95% of steel grades. It melts at 1,420°C (2,588 °F). A900 is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- High strength — 1,030 MPa (149 ksi), better than 93% of steel grades
- Good corrosion resistance — 25/100, better than 92% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- High embodied carbon — 7.5 kg CO₂/kg, worse than 99% of steel grades
- Limited formability — 8/100, worse than 97% of steel grades
- Poor heat conductor — 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades
- Difficult to machine — 30/100, worse than 89% of steel grades
AerMet 310-ANN properties
Typical room-temperature values for AerMet 310-ANN; 10 are specific to this condition. Other listed values are AerMet 310 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
AerMet 310-ANN has a density of 8 g/cm³ (0.289 lb/in³), heavier than 95% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
AerMet 310-ANN has a yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,280 MPa (186 ksi) — stronger than 93% of steel grades. Elongation at break is 15% and the elastic modulus is 194 GPa (28.1 Msi).
Thermal6
AerMet 310-ANN is rated for continuous service to 400°C (752 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical2
AerMet 310-ANN has an electrical resistivity of 6.5×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability4
Producing a kilogram of AerMet 310-ANN takes about 100 MJ of energy and emits 7.5 kg of CO₂ — more than 99% of steel grades. Typical recycled content is 20%.
Manufacturability7
AerMet 310-ANN's machinability is poor (30/100, worse than 89% of steel grades); weldability fair (45/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AerMet 310-ANN
Is AerMet 310 easy to machine?
Rough machine in the annealed (~40 HRC) condition; finish machining at 55–58 HRC needs rigid setups, ceramic/CBN or coated carbide, low speeds and generous coolant, with grinding for final tolerances.
Can AerMet 310 be welded?
GTAW or electron-beam welding with matching filler and no preheat is practical; re-solution + re-age (or at least re-age) after welding to restore properties, and keep hydrogen and moisture out.
Can AerMet 310 be formed, bent or molded?
Hot work only (forge ~1100–1150 °C, finish above 900 °C); essentially no cold formability at hardened strength levels.
What surface finishes work on AerMet 310?
Not stainless — protect with low-hydrogen cadmium, IVD aluminium or HVOF coatings; bake at 190 °C after any electroplating or pickling to avoid hydrogen embrittlement, and shot peen high-stress fillets.
AerMet 310 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 | 0.23 – 0.27 | 0.25 |
| Co | 14.5 – 15.5 | 15 |
| Ni | 10.7 – 11.3 | 11 |
| Cr | 2.2 – 2.6 | 2.4 |
| Mo | 1.2 – 1.6 | 1.4 |
| Mnresidual | ≤ 0.1 | — |
| Siresidual | ≤ 0.1 | — |
| P | ≤ 0.01 | — |
| S | ≤ 0.01 | — |
| Fe | balance | — |
AerMet 310-ANN — frequently asked
What is AerMet 310-ANN used for?
AerMet 310-ANN is typically used for landing gear, arresting hooks and high-load aircraft structural parts. In short: highest-strength AerMet grade; 310 ksi tensile class; toughness at extreme strength.
What is the yield strength of AerMet 310-ANN?
AerMet 310-ANN has a typical yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,280 MPa (186 ksi) — stronger than 93% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is AerMet 310-ANN easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Rough machine in the annealed (~40 HRC) condition; finish machining at 55–58 HRC needs rigid setups, ceramic/CBN or coated carbide, low speeds and generous coolant, with grinding for final tolerances.
Can AerMet 310-ANN be welded?
With care — weldability is rated fair (45/100). GTAW or electron-beam welding with matching filler and no preheat is practical; re-solution + re-age (or at least re-age) after welding to restore properties, and keep hydrogen and moisture out.
What surface finishes work on AerMet 310-ANN?
Not stainless — protect with low-hydrogen cadmium, IVD aluminium or HVOF coatings; bake at 190 °C after any electroplating or pickling to avoid hydrogen embrittlement, and shot peen high-stress fillets.
Can AerMet 310-ANN be formed, bent or molded?
Hot work only (forge ~1100–1150 °C, finish above 900 °C); essentially no cold formability at hardened strength levels.
What is the maximum service temperature of AerMet 310-ANN?
AerMet 310-ANN 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 AerMet 310-A900 and AerMet 310-ANN?
A900 is the default condition — standard aerospace heat treatment giving the nominal ~310 ksi strength with usable K_IC — the design condition for landing gear and structural parts. ANN: mill-supplied soft condition (~40 HRC max) for rough machining before final heat treatment. Yield strength is 1,960 MPa in A900 versus 1,030 MPa in ANN.
Sources
- AerMet 310 Alloy technical datasheet — Carpenter Technology Corporation (2020)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- MMPDS-17 (ultra-high-strength steel chapter, AerMet-class data) — Battelle/FAA (2022)
- AMS 6532 / AMS 6478 (AerMet-family Co-Ni ultra-high-strength steel bar and forgings) — SAE International (2019)
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.