Nickel Alloy 2.4878 +AT (Solution annealed)
Heat-treated state
EN 2.4878
Choose for forming, deep machining or as raw stock before the customer's own precipitation ageing.
Values for the +AT condition
Other 2.4878 tempers and conditions
2.4878 is listed in 5 conditions; see the grade overview at 2.4878.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ATThis page Solution annealed | Choose for forming, deep machining or as raw stock before the customer's own precipitation ageing. | 450 | 900 | 40 | 220 HB | — |
As forged / hot rolled, unheat-treated stock | Semi-finished forging or billet stock intended for further hot work and a full solution + ageing cycle at the part maker. | 560 | 1,000 | 30 | 25 HRC | 1.4 % IACS |
Precipitation hardened | Choose where long-term creep and stress-relaxation resistance above ~650 °C matter more than peak room-temperature strength; the higher solution temperature coarsens the grain. | 760 | 1,190 | 20 | 34 HRC | — |
+P1080Default Precipitation hardened | Standard high-strength bolting condition: finer grain from the lower solution temperature gives the highest room-temperature proof strength. | 820 | 1,250 | 18 | 37 HRC | — |
Cold drawn / cold worked then precipitation hardened bar & wire | Small-diameter fastener and spring stock where cold work plus ageing lifts proof strength above the standard +P conditions. | 980 | 1,380 | 12 | 41 HRC | — |
What is 2.4878 +AT?
2.4878 +AT is 2.4878 heat treated to +AT — choose for forming, deep machining or as raw stock before the customer's own precipitation ageing. 2.4878 +AT has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 66% of nickel alloy grades. Elongation at break is 40% and the elastic modulus is 213 GPa (30.9 Msi). 2.4878 +AT has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 63% of nickel alloy grades. It melts at 1,310°C (2,390 °F). +P1080 is the default condition FabDigit quotes; +AT is available on request or by drawing note.
2.4878 +AT properties
Typical room-temperature values for 2.4878 +AT; 13 are specific to this condition. Other listed values are 2.4878 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
2.4878 +AT has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 63% of nickel alloy grades. It melts at 1,310°C (2,390 °F).
Mechanical16
2.4878 +AT has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 66% of nickel alloy grades. Elongation at break is 40% and the elastic modulus is 213 GPa (30.9 Msi).
Thermal6
2.4878 +AT is rated for continuous service to 700°C (1,292 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 60% of nickel alloy grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
2.4878 +AT conducts electricity at 1.4 % IACS, worse than 65% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 51% of nickel alloy grades.
Sustainability4
Producing a kilogram of 2.4878 +AT takes about 150 MJ of energy and emits 13 kg of CO₂ — less than 68% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability7
2.4878 +AT's machinability is poor (20/100, better than 53% of nickel alloy grades); weldability fair (45/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 2.4878 +AT
Is 2.4878 easy to machine?
Machine preferably in the solution-annealed state with rigid setups, positive-rake carbide or ceramic tooling, low surface speed, heavy constant feed and flood coolant to avoid work hardening and glazing.
Can 2.4878 be welded?
GTAW with matched or Ni-Cr-Mo filler in the solution-annealed condition; the alloy is strain-age crack sensitive, so weld cold, minimise restraint and re-solution/age after welding.
Can 2.4878 be formed, bent or molded?
Hot work between about 1100 and 950 °C; cold forming is only practical in the +AT condition and requires high press loads plus intermediate annealing.
What surface finishes work on 2.4878?
Not anodizable — use pickling/passivation, electropolishing, shot peening of thread roots for fatigue life, or aluminide/thermal-barrier coatings for hot-gas service.
2.4878 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 |
|---|---|---|
| Ccarbide former for grain-boundary strength | 0.03 – 0.1 | 0.06 |
| Croxidation/hot corrosion resistance | 23 – 26 | 25 |
| Co | 18 – 22 | 20 |
| Mosolid-solution strengthening | 3 – 5 | 4 |
| Tiγ′ former | 1.8 – 2.7 | 2.3 |
| Alγ′ former | 0.8 – 1.6 | 1.2 |
| Feresidual | ≤ 2 | 0.8 |
| Mn | ≤ 1 | 0.3 |
| Si | ≤ 1 | 0.3 |
| Bcreep-ductility micro-addition | 0 – 0.01 | 0.01 |
| Zr | ≤ 0.1 | 0.03 |
| Cu | ≤ 0.2 | — |
| S | ≤ 0.02 | — |
| P | ≤ 0.02 | — |
| Nibalance, typically 43–50 % | balance | — |
2.4878 +AT — frequently asked
What is 2.4878 +AT used for?
2.4878 +AT is typically used for gas turbine fasteners, high-temperature bolting and turbine hot-section hardware. In short: waspaloy-class bolting alloy; 1250 MPa at 730 °C service; hardest to machine of family.
What is the yield strength of 2.4878 +AT?
2.4878 +AT has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 66% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is 2.4878 +AT easy to machine?
Not especially — machinability is rated poor (20/100, better than 53% of nickel alloy grades). Machine preferably in the solution-annealed state with rigid setups, positive-rake carbide or ceramic tooling, low surface speed, heavy constant feed and flood coolant to avoid work hardening and glazing.
Can 2.4878 +AT be welded?
With care — weldability is rated fair (45/100). GTAW with matched or Ni-Cr-Mo filler in the solution-annealed condition; the alloy is strain-age crack sensitive, so weld cold, minimise restraint and re-solution/age after welding.
What surface finishes work on 2.4878 +AT?
Not anodizable — use pickling/passivation, electropolishing, shot peening of thread roots for fatigue life, or aluminide/thermal-barrier coatings for hot-gas service.
Can 2.4878 +AT be formed, bent or molded?
Hot work between about 1100 and 950 °C; cold forming is only practical in the +AT condition and requires high press loads plus intermediate annealing.
What is the maximum service temperature of 2.4878 +AT?
2.4878 +AT is rated for continuous use to about 700°C (1,292 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10269 — Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties — CEN (2013)
- EN 10302 — Creep resisting steels, nickel and cobalt alloys — CEN (2008)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys (Ni-base superalloys) — ASM International (1990)
- Superalloys: A Technical Guide, 2nd ed. — ASM International (2002)
- Nickel-base precipitation-hardening bolting alloy datasheets (Waspaloy / Nimonic 90 class) — Special Metals / Böhler (2020)
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.