Refractory Metal T-222 ANN+AGE
Precip hard
ANN+AGE = annealed + carbide aged
Post-anneal ageing to precipitate fine (Hf,Ta)C for maximum creep strength in long-life high-temperature service.
Values for the ANN+AGE condition
Other T-222 tempers and conditions
T-222 is listed in 4 conditions; see the grade overview at T-222.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stocked condition for sheet, plate and rod: best ductility and formability with carbide strengthening intact. | 470 | 600 | 22 | 24 HRC | 4.1 % IACS |
ANN+AGEThis page Annealed + carbide aged | Post-anneal ageing to precipitate fine (Hf,Ta)C for maximum creep strength in long-life high-temperature service. | 540 | 660 | 18 | 28 HRC | 4 % IACS |
Stress relieved | Choose when higher room-temperature strength is wanted but residual forming stresses must be removed. | 660 | 760 | 12 | 31 HRC | 4 % IACS |
Cold worked | Highest room-temperature strength for wire, foil and thin strip; recrystallizes and loses the cold-work benefit above ~1300 °C. | 880 | 950 | 5 | 37 HRC | 3.9 % IACS |
What is T-222 ANN+AGE?
T-222 ANN+AGE is T-222 in the ANN+AGE condition — post-anneal ageing to precipitate fine (Hf,Ta)C for maximum creep strength in long-life high-temperature service. T-222 ANN+AGE has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 76% of refractory metal grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi). T-222 ANN+AGE has a density of 16.9 g/cm³ (0.611 lb/in³), heavier than 91% of refractory metal grades. It melts at 3,030°C (5,486 °F). ANN is the default condition FabDigit quotes; ANN+AGE is available on request or by drawing note.
Advantages
- High service temperature — 2,500°C (4,532 °F), better than 101% of refractory metal grades
- High strength — 540 MPa (78.3 ksi), better than 76% of refractory metal grades
Limitations
- High embodied carbon — 265 kg CO₂/kg, worse than 95% of refractory metal grades
- Heavy — 16.9 g/cm³ (0.611 lb/in³), worse than 91% of refractory metal grades
- Difficult to machine — 15/100, worse than 83% of refractory metal grades
T-222 ANN+AGE properties
Typical room-temperature values for T-222 ANN+AGE; 22 are specific to this condition. Other listed values are T-222 reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
T-222 ANN+AGE has a density of 16.9 g/cm³ (0.611 lb/in³), heavier than 91% of refractory metal grades. It melts at 3,030°C (5,486 °F).
Mechanical16
T-222 ANN+AGE has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 76% of refractory metal grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
T-222 ANN+AGE is rated for continuous service to 2,500°C (4,532 °F). It conducts heat at 41 W/m·K (23.7 BTU/hr·ft·°F), worse than 53% of refractory metal grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical3
T-222 ANN+AGE conducts electricity at 4 % IACS, worse than 67% of refractory metal grades.
Chemical & Environmental2
Corrosion resistance is excellent (92/100), better than 86% of refractory metal grades.
Sustainability3
Producing a kilogram of T-222 ANN+AGE takes about 4,400 MJ of energy and emits 265 kg of CO₂ — more than 94% of refractory metal grades. Typical recycled content is 20%.
Manufacturability7
T-222 ANN+AGE's machinability is poor (15/100, worse than 83% of refractory metal grades); weldability good (55/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with T-222 ANN+AGE
Is T-222 easy to machine?
Gummy and galling-prone: use sharp positive-rake carbide, slow speeds, heavy flood coolant and rigid setups; avoid dwelling and rubbing.
Can T-222 be welded?
EB or GTAW in a high-purity argon glovebox or vacuum chamber only — ppm-level O/N/H pickup embrittles the weld; no post-weld air exposure while hot.
Can T-222 be formed, bent or molded?
Cold rolls, deep-draws and bends well in the annealed condition; interstage vacuum anneals at 1300–1600 °C restore ductility, and hot work must be done in vacuum or inert gas.
What surface finishes work on T-222?
Pickle in HF-HNO₃ mixtures to remove contaminated layers; mechanically polishes to a bright finish; requires a protective coating (silicide/aluminide) or inert atmosphere for any service above ~300 °C.
T-222 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 |
|---|---|---|
| Wsolid-solution strengthener | 9 – 11 | 9.6 |
| Hfcarbide former; some Chinese listings mis-state this as Nb | 2 – 2.8 | 2.4 |
| Cforms (Hf,Ta)C dispersoids | 0.01 – 0.02 | 0.01 |
| Ointerstitial impurity limit | ≤ 0.02 | — |
| Ninterstitial impurity limit | ≤ 0.01 | — |
| Fe | ≤ 0.01 | — |
| Nbresidual from Ta feedstock | ≤ 0.5 | — |
| Ta | balance | — |
T-222 ANN+AGE — frequently asked
What is T-222 ANN+AGE used for?
T-222 ANN+AGE is typically used for space nuclear reactor fuel cladding, rocket nozzle components, high-temperature structural parts and thermionic converter emitters. In short: highest-creep tantalum alloy; 2400 °C vacuum service; ductile, deep-drawable refractory metal.
What is the yield strength of T-222 ANN+AGE?
T-222 ANN+AGE has a typical yield strength of 540 MPa (78.3 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 76% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.
Is T-222 ANN+AGE easy to machine?
Not especially — machinability is rated poor (15/100, worse than 83% of refractory metal grades). Gummy and galling-prone: use sharp positive-rake carbide, slow speeds, heavy flood coolant and rigid setups; avoid dwelling and rubbing.
Can T-222 ANN+AGE be welded?
Yes — weldability is rated good (55/100). EB or GTAW in a high-purity argon glovebox or vacuum chamber only — ppm-level O/N/H pickup embrittles the weld; no post-weld air exposure while hot.
What surface finishes work on T-222 ANN+AGE?
Pickle in HF-HNO₃ mixtures to remove contaminated layers; mechanically polishes to a bright finish; requires a protective coating (silicide/aluminide) or inert atmosphere for any service above ~300 °C.
Can T-222 ANN+AGE be formed, bent or molded?
Cold rolls, deep-draws and bends well in the annealed condition; interstage vacuum anneals at 1300–1600 °C restore ductility, and hot work must be done in vacuum or inert gas.
What is the maximum service temperature of T-222 ANN+AGE?
T-222 ANN+AGE is rated for continuous use to about 2,500°C (4,532 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between T-222-ANN and T-222-CW?
ANN is the default condition — standard stocked condition for sheet, plate and rod: best ductility and formability with carbide strengthening intact. CW: highest room-temperature strength for wire, foil and thin strip; recrystallizes and loses the cold-work benefit above ~1300 °C. Yield strength is 470 MPa in ANN versus 880 MPa in CW.
Sources
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (refractory metals section) — ASM International (1990)
- Refractory Metals and Alloys — properties of Ta-W-Hf-C alloys (T-111, T-222, ASTAR series) — NASA Lewis / AEC space-power program reports (1970)
- ASTM B708 — Tantalum and Tantalum Alloy Plate, Sheet and Strip — ASTM International (2021)
- Tantalum alloy mill product datasheets (sheet, rod, wire) — H.C. Starck / Global Advanced Metals / (2023)
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.