Refractory Metal Pure Ta Stress Relieved
Heat-treated state
UNS R05200 · ASTM B365 · also Ta CP
Pick when dimensional stability and springback control are needed but full recrystallization softness is not wanted; keeps a useful part of the cold-worked strength.
Values for the Stress Relieved condition
Other Pure Ta tempers and conditions
Pure Ta is listed in 6 conditions; see the grade overview at Pure Ta.
- R05400 EBM
- Vacuum Annealed
- R05200 PM
- Stress Relieved
- As Rolled
- CW Hard
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
R05400 | Choose for sputtering targets, high-temperature furnace parts and implants where low interstitial content, large grain purity and maximum ductility are required. | 150 | 225 | 42 | 85 HB | 13.2 % IACS |
Vacuum AnnealedDefault recrystallized, softest condition | Default stocked condition for sheet, plate, rod and tube: maximum ductility for deep drawing, spinning, bending and lining work, and lowest gas content. | 170 | 250 | 38 | 95 HB | 12.8 % IACS |
R05200 | Standard commercial purity route (ASTM B708/B365 type R05200); slightly higher interstitials and strength than EB-melted material, adequate for chemical equipment. | 180 | 260 | 35 | 100 HB | 12.5 % IACS |
Stress RelievedThis page partially annealed, worked structure retained | Pick when dimensional stability and springback control are needed but full recrystallization softness is not wanted; keeps a useful part of the cold-worked strength. | 270 | 340 | 20 | 128 HB | 12.6 % IACS |
cold rolled, not annealed (approx. 40–70 % CW) | Use for stiffer sheet, foil, shielding and target backing plates where higher yield strength matters more than drawability. | 390 | 450 | 8 | 88 HRB | 12.3 % IACS |
Heavily cold worked wire/foil | Fine wire, springs and capacitor lead wire where maximum strength and stiffness per section is required. | 560 | 620 | 3 | 20 HRC | 12.4 % IACS |
What is Pure Ta Stress Relieved?
Pure Ta Stress Relieved is Pure Ta heat treated to Stress Relieved — pick when dimensional stability and springback control are needed but full recrystallization softness is not wanted; keeps a useful part of the cold-worked strength. Pure Ta Stress Relieved has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 64% of refractory metal grades. Elongation at break is 20% and the elastic modulus is 186 GPa (27 Msi). Pure Ta Stress Relieved has a density of 16.6 g/cm³ (0.6 lb/in³), heavier than 84% of refractory metal grades. It melts at 2,996°C (5,425 °F). Vacuum Annealed is the default condition FabDigit quotes; Stress Relieved is available on request or by drawing note.
Advantages
- Good corrosion resistance — 97/100, better than 97% of refractory metal grades
- Forms and bends easily — 70/100, better than 75% of refractory metal grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 95% of refractory metal grades
- High embodied carbon — 260 kg CO₂/kg, worse than 92% of refractory metal grades
- Heavy — 16.6 g/cm³ (0.6 lb/in³), worse than 84% of refractory metal grades
Pure Ta Stress Relieved properties
Typical room-temperature values for Pure Ta Stress Relieved; 20 are specific to this condition. Other listed values are Pure Ta reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
Pure Ta Stress Relieved has a density of 16.6 g/cm³ (0.6 lb/in³), heavier than 84% of refractory metal grades. It melts at 2,996°C (5,425 °F).
Mechanical13
Pure Ta Stress Relieved has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 64% of refractory metal grades. Elongation at break is 20% and the elastic modulus is 186 GPa (27 Msi).
Thermal6
Pure Ta Stress Relieved 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
Pure Ta Stress Relieved conducts electricity at 12.6 % IACS, better than 68% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (97/100), better than 97% of refractory metal grades.
Sustainability4
Producing a kilogram of Pure Ta Stress Relieved takes about 4,200 MJ of energy and emits 260 kg of CO₂ — more than 91% of refractory metal grades. Typical recycled content is 25%.
Manufacturability8
Pure Ta Stress Relieved's machinability is poor (26/100, worse than 60% of refractory metal grades); weldability good (65/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Pure Ta Stress Relieved
Is Pure Ta easy to machine?
Very gummy and prone to galling: use sharp high-positive-rake carbide or HSS, slow speeds (~15–25 m/min), heavy feed, generous chlorinated or emulsion coolant, and never let the tool dwell.
Can Pure Ta be welded?
GTAW/EBW/laser welds cleanly only in vacuum or high-purity argon/helium chambers with full backside shielding — any O₂, N₂ or H₂ pickup above ~50 ppm causes severe embrittlement; no filler normally needed.
Can Pure Ta be formed, bent or molded?
Excellent cold formability — deep drawing, spinning, hydroforming and tight bends in the annealed state; use non-galling tooling with PTFE/oil interlayers and interstage vacuum anneals at 1000–1300 °C.
What surface finishes work on Pure Ta?
Pickle in HF/HNO₃ to remove oxide, then electropolish for chemical or implant service; anodizing produces stable colored Ta₂O₅ films, and no paint or plating is needed for corrosion protection.
Pure Ta 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 |
|---|---|---|
| Nbprincipal metallic impurity | ≤ 0.1 | 0.03 |
| Ointerstitial; embrittles if high | ≤ 0.02 | 0.01 |
| N | ≤ 0.01 | 0 |
| C | ≤ 0.01 | 0 |
| H | ≤ 0 | 5×10⁻⁴ |
| W | ≤ 0.05 | 0.01 |
| Mo | ≤ 0.02 | 0.01 |
| Fe | ≤ 0.01 | 0 |
| Ti | ≤ 0.01 | 0 |
| Ni | ≤ 0.01 | 0 |
| Si | ≤ 0.01 | 0 |
| Tabalance, metallic basis (Nb excluded from purity count per ASTM) | ≥ 99.9 (balance) | — |
Pure Ta Stress Relieved — frequently asked
What is Pure Ta Stress Relieved used for?
Pure Ta Stress Relieved is typically used for chemical process vessel liners and cladding, heat exchanger tubing and bayonet heaters, capacitor anodes, surgical implants and radiopaque markers, rupture discs and thermowells and furnace heat shields and crucibles. In short: corrosion-proof tantalum plate.
What is the yield strength of Pure Ta Stress Relieved?
Pure Ta Stress Relieved has a typical yield strength of 270 MPa (39.2 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 64% of refractory metal grades. Strength varies by condition: see the 6 listed tempers.
Is Pure Ta Stress Relieved easy to machine?
Not especially — machinability is rated poor (26/100, worse than 60% of refractory metal grades). Very gummy and prone to galling: use sharp high-positive-rake carbide or HSS, slow speeds (~15–25 m/min), heavy feed, generous chlorinated or emulsion coolant, and never let the tool dwell.
Can Pure Ta Stress Relieved be welded?
Yes — weldability is rated good (65/100). GTAW/EBW/laser welds cleanly only in vacuum or high-purity argon/helium chambers with full backside shielding — any O₂, N₂ or H₂ pickup above ~50 ppm causes severe embrittlement; no filler normally needed.
What surface finishes work on Pure Ta Stress Relieved?
Pickle in HF/HNO₃ to remove oxide, then electropolish for chemical or implant service; anodizing produces stable colored Ta₂O₅ films, and no paint or plating is needed for corrosion protection.
Can Pure Ta Stress Relieved be formed, bent or molded?
Excellent cold formability — deep drawing, spinning, hydroforming and tight bends in the annealed state; use non-galling tooling with PTFE/oil interlayers and interstage vacuum anneals at 1000–1300 °C.
What is the maximum service temperature of Pure Ta Stress Relieved?
Pure Ta Stress Relieved 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.
Sources
- ASTM B708 — Tantalum and Tantalum Alloy Plate, Sheet, and Strip — ASTM International (2021)
- ASTM B365 — Tantalum and Tantalum Alloy Rod and Wire — ASTM International (2018)
- ASTM B521 — Tantalum and Tantalum Alloy Seamless and Welded Tubes — ASTM International (2018)
- ASM Handbook Vol. 2 — Properties of Refractory Metals and Alloys — ASM International (1990)
- CRC Handbook of Chemistry and Physics — CRC Press (2020)
- Tantalum metal product data (sheet, rod, tube) — H.C. Starck / Global Advanced Metals (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.