Refractory Metal R05400-O (Annealed)
Temper · default condition
UNS R05400 · ASTM B365
Default stocked condition: maximum ductility for deep drawing, spinning and lining fabrication.
Values for the O condition
Other R05400 tempers and conditions
R05400 is listed in 3 conditions; see the grade overview at R05400.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ODefaultThis page Annealed | Default stocked condition: maximum ductility for deep drawing, spinning and lining fabrication. | 170 | 250 | 35 | 90 HB | 12.8 % IACS |
Stress relieved | Intermediate condition: relieves cold-work stresses and improves dimensional stability while retaining much of the cold-worked strength. | 310 | 400 | 15 | 140 HB | 12.5 % IACS |
Cold worked | Pick when higher strength and stiffness of thin foil, wire or springs matters more than formability. | 480 | 550 | 5 | 185 HB | 12.1 % IACS |
What is R05400-O?
R05400-O is R05400 in the O temper — default stocked condition: maximum ductility for deep drawing, spinning and lining fabrication. R05400-O has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 93% of refractory metal grades. Elongation at break is 35% and the elastic modulus is 186 GPa (27 Msi). R05400-O has a density of 16.6 g/cm³ (0.6 lb/in³), heavier than 84% of refractory metal grades. It melts at 3,017°C (5,463 °F).
Advantages
- Good corrosion resistance — 98/100, better than 100% of refractory metal grades
- Forms and bends easily — 95/100, better than 99% of refractory metal grades
- Tough — resists crack growth — 100 MPa·√m (91 ksi·√in), better than 98% of refractory metal grades
- Ductile — tolerates forming and impact — 35%, better than 93% of refractory metal grades
- Readily welded — 78/100, better than 86% of refractory metal grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 95% of refractory metal grades
- Low strength — 170 MPa (24.7 ksi), worse than 93% of refractory metal grades
- High embodied carbon — 250 kg CO₂/kg, worse than 89% of refractory metal grades
- Heavy — 16.6 g/cm³ (0.6 lb/in³), worse than 84% of refractory metal grades
R05400-O properties
Typical room-temperature values for R05400-O; 19 are specific to this condition. Other listed values are R05400 reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
R05400-O has a density of 16.6 g/cm³ (0.6 lb/in³), heavier than 84% of refractory metal grades. It melts at 3,017°C (5,463 °F).
Mechanical14
R05400-O has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 93% of refractory metal grades. Elongation at break is 35% and the elastic modulus is 186 GPa (27 Msi).
Thermal6
R05400-O is rated for continuous service to 300°C (572 °F). It conducts heat at 57 W/m·K (32.9 BTU/hr·ft·°F), better than 68% of refractory metal grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical3
R05400-O conducts electricity at 12.8 % IACS, better than 69% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (98/100), better than 100% of refractory metal grades.
Sustainability4
Producing a kilogram of R05400-O takes about 4,000 MJ of energy and emits 250 kg of CO₂ — more than 89% of refractory metal grades. Typical recycled content is 30%.
Manufacturability8
R05400-O's machinability is poor (22/100, worse than 73% of refractory metal grades); weldability very good (78/100); formability excellent (95/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with R05400-O
Is R05400 easy to machine?
Very gummy and galling-prone — use sharp, highly positive-rake carbide or HSS tools, heavy chlorinated or sulfurized coolant, slow speeds (15–30 m/min) and generous feeds to avoid rubbing; never let the tool dwell.
Can R05400 be welded?
GTAW in a high-purity argon glovebox, EB or laser welding only; any pickup of O₂, N₂ or H₂ during welding causes severe embrittlement, and Ta must not be welded to Fe/Ni alloys directly.
Can R05400 be formed, bent or molded?
Outstanding cold formability — deep draws, spinning and >90 % cold rolling are routine with clean tooling and non-galling lubricants; vacuum anneal at 1100–1300 °C to restore ductility between severe operations.
What surface finishes work on R05400?
Chemically clean/pickle in HF–HNO₃ then electropolish; anodizing in dilute phosphoric or citric electrolyte builds a controlled Ta₂O₅ film for dielectric or colored finishes; avoid abrasive smearing.
R05400 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 |
|---|---|---|
| Nbcolumbium | ≤ 0.1 | 0.03 |
| W | ≤ 0.05 | 0.01 |
| Mo | ≤ 0.02 | 0.01 |
| Ti | ≤ 0.01 | 0 |
| Fe | ≤ 0.01 | 0 |
| Ni | ≤ 0.01 | 0 |
| Si | ≤ 0.01 | 0 |
| C | ≤ 0.01 | 0 |
| Ohigher than EB-melted R05200 (0.015 max) because of powder-metallurgy route | ≤ 0.03 | 0.02 |
| N | ≤ 0.01 | 0 |
| H | ≤ 0 | 5×10⁻⁴ |
| Ta99.9 % min (Ta+Nb basis per ASTM B365/B708 Type 2) | balance | — |
R05400-O — frequently asked
What is R05400-O used for?
R05400-O is typically used for capacitor anode powder feedstock, sputtering target blanks, mill product starting stock and electronic grade tantalum components. In short: baseline unalloyed tantalum; near-inert to acids; deep-draw capable.
What is the yield strength of R05400-O?
R05400-O has a typical yield strength of 170 MPa (24.7 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 93% of refractory metal grades. Strength varies by condition: see the 3 listed tempers.
Is R05400-O easy to machine?
Not especially — machinability is rated poor (22/100, worse than 73% of refractory metal grades). Very gummy and galling-prone — use sharp, highly positive-rake carbide or HSS tools, heavy chlorinated or sulfurized coolant, slow speeds (15–30 m/min) and generous feeds to avoid rubbing; never let the tool dwell.
Can R05400-O be welded?
Yes — weldability is rated very good (78/100). GTAW in a high-purity argon glovebox, EB or laser welding only; any pickup of O₂, N₂ or H₂ during welding causes severe embrittlement, and Ta must not be welded to Fe/Ni alloys directly.
What surface finishes work on R05400-O?
Chemically clean/pickle in HF–HNO₃ then electropolish; anodizing in dilute phosphoric or citric electrolyte builds a controlled Ta₂O₅ film for dielectric or colored finishes; avoid abrasive smearing.
Can R05400-O be formed, bent or molded?
Outstanding cold formability — deep draws, spinning and >90 % cold rolling are routine with clean tooling and non-galling lubricants; vacuum anneal at 1100–1300 °C to restore ductility between severe operations.
What is the maximum service temperature of R05400-O?
R05400-O is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between R05400-O and R05400-CW?
O is the default condition — default stocked condition: maximum ductility for deep drawing, spinning and lining fabrication. CW: pick when higher strength and stiffness of thin foil, wire or springs matters more than formability. Yield strength is 170 MPa in O versus 480 MPa in CW.
Sources
- ASTM B365 — Tantalum and Tantalum Alloy Rod and Wire — ASTM International (2018)
- ASTM B708 — Tantalum and Tantalum Alloy Plate, Sheet and Strip — ASTM International (2021)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (refractory metals) — ASM International (1990)
- CRC Handbook of Chemistry and Physics — physical properties of tantalum — CRC Press (2023)
- Tantalum mill product data (sheet, rod, wire) — Global Advanced Metals / H.C. Starck Solutions (2022)
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.