Refractory Metal Pure Ta CW Hard
Supply condition
UNS R05200 · ASTM B365 · also Ta CP
CW Hard = heavily cold worked wire/foil
Fine wire, springs and capacitor lead wire where maximum strength and stiffness per section is required.
Values for the CW Hard condition
Other Pure Ta tempers and conditions
Pure Ta is listed in 6 conditions; see the grade overview at Pure Ta.
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 |
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 |
CW HardThis page 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 CW Hard?
Pure Ta CW Hard is Pure Ta supplied in the CW Hard condition — fine wire, springs and capacitor lead wire where maximum strength and stiffness per section is required. Pure Ta CW Hard has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 78% of refractory metal grades. Elongation at break is 3% and the elastic modulus is 186 GPa (27 Msi). Pure Ta CW Hard 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; CW Hard is available on request or by drawing note.
Advantages
- Good corrosion resistance — 96/100, better than 96% of refractory metal grades
- High strength — 560 MPa (81.2 ksi), better than 78% of refractory metal grades
Limitations
- Limited service temperature — 250°C (482 °F), worse than 100% of refractory metal grades
- High embodied carbon — 260 kg CO₂/kg, worse than 92% of refractory metal grades
- Limited ductility — 3%, worse than 88% of refractory metal grades
- Heavy — 16.6 g/cm³ (0.6 lb/in³), worse than 84% of refractory metal grades
Pure Ta CW Hard properties
Typical room-temperature values for Pure Ta CW Hard; 22 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 CW Hard 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 CW Hard has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 78% of refractory metal grades. Elongation at break is 3% and the elastic modulus is 186 GPa (27 Msi).
Thermal6
Pure Ta CW Hard is rated for continuous service to 250°C (482 °F). It conducts heat at 55 W/m·K (31.8 BTU/hr·ft·°F), better than 67% of refractory metal grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical3
Pure Ta CW Hard conducts electricity at 12.4 % IACS, better than 68% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (96/100), better than 96% of refractory metal grades.
Sustainability4
Producing a kilogram of Pure Ta CW Hard 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 CW Hard's machinability is fair (35/100, better than 81% of refractory metal grades); weldability good (55/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Pure Ta CW Hard
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 CW Hard — frequently asked
What is Pure Ta CW Hard used for?
Pure Ta CW Hard 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 CW Hard?
Pure Ta CW Hard has a typical yield strength of 560 MPa (81.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 78% of refractory metal grades. Strength varies by condition: see the 6 listed tempers.
Is Pure Ta CW Hard easy to machine?
Not especially — machinability is rated fair (35/100, better than 81% 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 CW Hard be welded?
Yes — weldability is rated good (55/100). 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 CW Hard?
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 CW Hard 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 CW Hard?
Pure Ta CW Hard is rated for continuous use to about 250°C (482 °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.