Refractory Metal C-129Y
UNS R04360
C-129Y (UNS R04360) is a niobium–tungsten–hafnium alloy doped with yttrium, which gives higher creep strength than C-103 at elevated temperature.
Reference datasheet — C-129Y 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 Annealed condition
C-129Y tempers and conditions
C-129Y is supplied in 3 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault recrystallization annealed sheet/plate (vacuum, ~1300–1500 °C) | Standard stocked condition for sheet and plate: best ductility and formability, baseline strength for hot-structure design. | 480 | 585 | 22 | 18 HRC | 3.6 % IACS |
Stress relieved | Choose when higher room-temperature strength is wanted with usable ductility and dimensional stability after forming. | 620 | 700 | 12 | 24 HRC | 3.5 % IACS |
Cold worked | Maximum room-temperature strength for thin sheet, foil and wire where no high-temperature exposure will recrystallize the material. | 830 | 900 | 6 | 30 HRC | 3.4 % IACS |
Supply forms, finishes and certifications
Ways C-129Y is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Annealed-Bar | Annealed bar / rod / forging | Supply form |
Coated-R512E | Silicide coated (R512E, Si-20Cr-20Fe slurry-fused) on annealed substrate | Supply form |
What is C-129Y?
C-129Y (UNS R04360) is a niobium–tungsten–hafnium alloy doped with yttrium, which gives higher creep strength than C-103 at elevated temperature. It is supplied as annealed, stress-relieved or cold-worked sheet and bar, often with an R512E silicide coating, for hot structures and propulsion hardware rated to about 1400 °C at 480 MPa yield, 585 MPa tensile and 22 % elongation. Like other niobium alloys it needs a silicide coating for oxidising service and picks up embrittling oxygen and nitrogen when welded, so joining is done in vacuum or high-purity argon. C-103 is the more available alternative. C-129Y has a density of 9.46 g/cm³ (0.342 lb/in³), heavier than 59% of refractory metal grades. It melts at 2,450°C (4,442 °F). C-129Y has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 585 MPa (84.8 ksi) — stronger than 72% of refractory metal grades. Elongation at break is 22% and the elastic modulus is 131 GPa (19 Msi).
What is C-129Y used for?
- rocket nozzle extensions
- high-temperature structural panels
- re-entry vehicle components
Advantages
- Tough — resists crack growth — 90 MPa·√m (81.9 ksi·√in), better than 94% of refractory metal grades
- High service temperature — 1,400°C (2,552 °F), better than 81% of refractory metal grades
C-129Y properties
Typical room-temperature values for C-129Y-Annealed; bars are the position among refractory metal grades.
Physical3
C-129Y has a density of 9.46 g/cm³ (0.342 lb/in³), heavier than 59% of refractory metal grades. It melts at 2,450°C (4,442 °F).
Mechanical17
C-129Y has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 585 MPa (84.8 ksi) — stronger than 72% of refractory metal grades. Elongation at break is 22% and the elastic modulus is 131 GPa (19 Msi).
Thermal6
C-129Y is rated for continuous service to 1,400°C (2,552 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 58% of refractory metal grades. Thermal expansion is 7.5 µm/m·K (4.17 µin/in·°F).
Electrical3
C-129Y conducts electricity at 3.6 % IACS, worse than 68% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), worse than 63% of refractory metal grades.
Sustainability4
Producing a kilogram of C-129Y takes about 620 MJ of energy and emits 42 kg of CO₂ — less than 67% of refractory metal grades. Typical recycled content is 25%.
Manufacturability7
C-129Y's machinability is poor (25/100, worse than 65% of refractory metal grades); weldability very good (70/100); formability good (65/100).
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. C-129Y is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C-129Y
Is C-129Y easy to machine?
Machine slow with sharp, positive-rake carbide or HSS-Co tooling, heavy rigid setups and flood coolant; it work-hardens and galls, so avoid dwell and take positive chip loads.
Can C-129Y be welded?
GTAW or EB weld in vacuum or high-purity argon with full backside shielding — oxygen/nitrogen pickup embrittles the weld; clean and degrease thoroughly and post-weld vacuum anneal where possible.
Can C-129Y be formed, bent or molded?
Sheet forms readily cold in the annealed condition with generous bend radii; heavy sections are worked warm (600–1000 °C) and vacuum annealed between passes.
C-129Y 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 | 10 |
| Hfcarbide/oxide strengthening, coating adherence | 9 – 11 | 10 |
| Yinterstitial scavenger | 0.05 – 0.15 | 0.1 |
| Zrresidual from Hf | ≤ 0.5 | |
| Taresidual | ≤ 0.5 | |
| C | ≤ 0.03 | 0.01 |
| O | ≤ 0.02 | 0.01 |
| N | ≤ 0.01 | 0.01 |
| H | ≤ 0 | |
| Fe | ≤ 0.05 | |
| Nb | balance |
What surface finishes work on C-129Y?
Chemically clean (HNO₃-HF pickle) then apply a fused silicide coating such as R512E for oxidation protection; decorative anodizing is possible but has no service value.
Equivalent designations
Standards and trade names that resolve to Refractory Metal C-129Y in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R04360
- Also called
- Nb-10W-10Hf-0.1Y
How much does C-129Y cost?
C-129Y 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.
C-129Y — frequently asked
What is C-129Y used for?
C-129Y is typically used for rocket nozzle extensions, high-temperature structural panels and re-entry vehicle components. In short: stronger creep than C-103; yttrium-doped Nb-W-Hf sheet; needs silicide coating in air.
What is the yield strength of C-129Y?
C-129Y has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 585 MPa (84.8 ksi) — stronger than 72% of refractory metal grades. Strength varies by condition: see the 3 listed tempers.
Is C-129Y easy to machine?
Not especially — machinability is rated poor (25/100, worse than 65% of refractory metal grades). Machine slow with sharp, positive-rake carbide or HSS-Co tooling, heavy rigid setups and flood coolant; it work-hardens and galls, so avoid dwell and take positive chip loads.
Can C-129Y be welded?
Yes — weldability is rated very good (70/100). GTAW or EB weld in vacuum or high-purity argon with full backside shielding — oxygen/nitrogen pickup embrittles the weld; clean and degrease thoroughly and post-weld vacuum anneal where possible.
What surface finishes work on C-129Y?
Chemically clean (HNO₃-HF pickle) then apply a fused silicide coating such as R512E for oxidation protection; decorative anodizing is possible but has no service value.
Can C-129Y be formed, bent or molded?
Sheet forms readily cold in the annealed condition with generous bend radii; heavy sections are worked warm (600–1000 °C) and vacuum annealed between passes.
What is the maximum service temperature of C-129Y?
C-129Y is rated for continuous use to about 1,400°C (2,552 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C-129Y Annealed and C-129Y-CW?
Annealed is the default condition — standard stocked condition for sheet and plate: best ductility and formability, baseline strength for hot-structure design. CW: maximum room-temperature strength for thin sheet, foil and wire where no high-temperature exposure will recrystallize the material. Yield strength is 480 MPa in Annealed versus 830 MPa in CW.
How much does C-129Y cost?
C-129Y 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)
- Aerospace Structural Metals Handbook — niobium (columbium) alloys — CINDAS/Purdue (1999)
- ASTM B652/B654 — Niobium-alloy bar, rod, sheet, strip and foil — ASTM International (2019)
- Refractory metal alloy datasheets (Nb-10W-10Hf-0.1Y, C-103, Cb-752) — specialty refractory metal producers (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.