Refractory Metal T-222
T-222 is a carbide-strengthened tantalum alloy (Ta-9.5W-2.4Nb-0.01C) developed for aerospace and nuclear service, combining solid-solution tungsten and niobium with dispersed carbides for the highest creep resistance among practical tantalum alloys.
Reference datasheet — T-222 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
T-222 tempers and conditions
T-222 is supplied in 4 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
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 |
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?
T-222 is a carbide-strengthened tantalum alloy (Ta-9.5W-2.4Nb-0.01C) developed for aerospace and nuclear service, combining solid-solution tungsten and niobium with dispersed carbides for the highest creep resistance among practical tantalum alloys. Annealed material gives 470 MPa yield, 600 MPa tensile and 22 % elongation, with a service ceiling near 2400 °C in vacuum or inert gas; stock is held in ANN, SR, CW and ANN+AGE conditions. It oxidizes rapidly in air above ~300 °C and needs a silicide or aluminide coating or a protective atmosphere; welding demands vacuum or a glovebox, machinability is low (18), and Ta-10W is the more available alternative. T-222 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). T-222 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 70% of refractory metal grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
What is T-222 used for?
- space nuclear reactor fuel cladding
- rocket nozzle components
- high-temperature structural parts
- thermionic converter emitters
Advantages
- High service temperature — 2,400°C (4,352 °F), better than 100% of refractory metal grades
- Tough — resists crack growth — 80 MPa·√m (72.8 ksi·√in), better than 91% 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 — 18/100, worse than 80% of refractory metal grades
T-222 properties
Typical room-temperature values for T-222-ANN; bars are the position among refractory metal grades.
Physical3
T-222 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 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 70% of refractory metal grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
T-222 is rated for continuous service to 2,400°C (4,352 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), better than 50% of refractory metal grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical3
T-222 conducts electricity at 4.1 % IACS, worse than 66% of refractory metal grades.
Chemical & Environmental2
Corrosion resistance is excellent (93/100), better than 92% of refractory metal grades.
Sustainability3
Producing a kilogram of T-222 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's machinability is poor (18/100, worse than 80% of refractory metal grades); weldability good (65/100); formability good (60/100).
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 refractory metal family
Yield strength against density for every refractory metal grade FabDigit runs. T-222 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with T-222
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.
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 | — |
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.
Equivalent designations
Standards and trade names that resolve to Refractory Metal T-222 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Other
- Ta-9.5W-2.4Nb-0.01C
How much does T-222 cost?
T-222 is a high-cost refractory metal ($$$$), pricier than about 78% 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.
T-222 — frequently asked
What is T-222 used for?
T-222 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?
T-222 has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 70% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.
Is T-222 easy to machine?
Not especially — machinability is rated poor (18/100, worse than 80% 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 be welded?
Yes — weldability is rated good (65/100). 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?
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 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?
T-222 is rated for continuous use to about 2,400°C (4,352 °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.
How much does T-222 cost?
T-222 is a high-cost refractory metal ($$$$), pricier than about 78% 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.
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; 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.