Refractory Metal R04261-CW (Cold worked)
Supply condition
UNS R04261 · ASTM B393 Type 4
Highest room-temperature strength and hardness for wire, thin strip and springs, but limited formability and it recrystallizes above ~1100 °C.
Values for the CW condition
Other R04261 tempers and conditions
R04261 is listed in 4 conditions; see the grade overview at R04261.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault vacuum recrystallization annealed (ASTM B393/B392 annealed condition) | Standard stocked condition for sheet, plate, bar and tube — maximum ductility for forming, welding and deep drawing. | 200 | 310 | 25 | 105 HB | 41 W/m·K |
Hot worked / as-forged bar and billet | Mill condition for heavy bar, forgings and machining stock where a final anneal is not required. | 260 | 380 | 20 | 124 HB | 8.4 % IACS |
Stress relieved | Choose when moderate strength must be combined with dimensional stability after cold forming or machining. | 340 | 420 | 15 | 143 HB | 8.4 % IACS |
CWThis page Cold worked | Highest room-temperature strength and hardness for wire, thin strip and springs, but limited formability and it recrystallizes above ~1100 °C. | 500 | 560 | 8 | 185 HB | — |
What is R04261-CW?
R04261-CW is R04261 supplied in the CW condition — highest room-temperature strength and hardness for wire, thin strip and springs, but limited formability and it recrystallizes above ~1100 °C. R04261-CW has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 75% of refractory metal grades. Elongation at break is 8% and the elastic modulus is 103 GPa (14.9 Msi). R04261-CW has a density of 8.57 g/cm³ (0.31 lb/in³), heavier than 51% of refractory metal grades. It melts at 2,410°C (4,370 °F). Annealed is the default condition FabDigit quotes; CW is available on request or by drawing note.
Advantages
- Easy to machine — 42/100, better than 97% of refractory metal grades
- Readily welded — 80/100, better than 92% of refractory metal grades
- High strength — 500 MPa (72.5 ksi), better than 75% of refractory metal grades
Limitations
- Limited ductility — 8%, worse than 75% of refractory metal grades
R04261-CW properties
Typical room-temperature values for R04261-CW; 12 are specific to this condition. Other listed values are R04261 reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
R04261-CW has a density of 8.57 g/cm³ (0.31 lb/in³), heavier than 51% of refractory metal grades. It melts at 2,410°C (4,370 °F).
Mechanical13
R04261-CW has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 75% of refractory metal grades. Elongation at break is 8% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
R04261-CW is rated for continuous service to 800°C (1,472 °F). It conducts heat at 41 W/m·K (23.7 BTU/hr·ft·°F), worse than 53% of refractory metal grades. Thermal expansion is 7.1 µm/m·K (3.94 µin/in·°F).
Electrical3
R04261-CW conducts electricity at 8.6 % IACS, better than 58% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 52% of refractory metal grades.
Sustainability4
Producing a kilogram of R04261-CW takes about 1,100 MJ of energy and emits 65 kg of CO₂ — less than 54% of refractory metal grades. Typical recycled content is 25%.
Manufacturability7
R04261-CW's machinability is fair (42/100, better than 97% of refractory metal grades); weldability very good (80/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with R04261-CW
Is R04261 easy to machine?
Gummy and galling-prone: use sharp high-positive-rake carbide or HSS tools, slow-to-moderate speeds, heavy feeds, chlorinated or flood coolant, and never let the tool dwell; degrease thoroughly before any high-temperature use.
Can R04261 be welded?
Excellent GTAW/EBW/laser weldability but only under high-purity argon trailing shield, glove box or vacuum — any O/N/H pickup above ~500 °C embrittles the weld; no filler needed for thin sections and no post-weld heat treatment other than vacuum stress relief.
Can R04261 be formed, bent or molded?
Very ductile cold: deep draws, spins, bends to tight radii at room temperature with lubricated tooling (avoid iron pickup); anneal 1100–1250 °C in vacuum between heavy reductions.
What surface finishes work on R04261?
Pickle in HNO3/HF mixtures to remove oxide (short exposure — HF attacks Nb), electropolish for high-purity or UHV surfaces, or anodise to a coloured Nb2O5 film; for service in air above ~400 °C an aluminide or silicide coating is mandatory.
R04261 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 |
|---|---|---|
| Zralloying addition; scavenges oxygen | 0.8 – 1.2 | 1 |
| C | ≤ 0.01 | — |
| Omax; looser than reactor grade R04251 | ≤ 0.03 | — |
| N | ≤ 0.01 | — |
| H | ≤ 0 | — |
| Fe | ≤ 0.01 | — |
| Ta | ≤ 0.1 | — |
| W | ≤ 0.05 | — |
| Mo | ≤ 0.02 | — |
| Hf | ≤ 0.02 | — |
| Ti | ≤ 0.03 | — |
| Si | ≤ 0.01 | — |
| Ni | ≤ 0.01 | — |
| Nbbalance; commercial grade per ASTM B391/B392/B393/B394 Type 4 | balance | — |
R04261-CW — frequently asked
What is R04261-CW used for?
R04261-CW is typically used for rocket nozzle liners, high-temperature furnace parts, chemical process equipment and vacuum tube components. In short: commercial Nb-1Zr workhorse; weldable and highly formable; hot service to 1200 °C.
What is the yield strength of R04261-CW?
R04261-CW has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 75% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.
Is R04261-CW easy to machine?
Not especially — machinability is rated fair (42/100, better than 97% of refractory metal grades). Gummy and galling-prone: use sharp high-positive-rake carbide or HSS tools, slow-to-moderate speeds, heavy feeds, chlorinated or flood coolant, and never let the tool dwell; degrease thoroughly before any high-temperature use.
Can R04261-CW be welded?
Yes — weldability is rated very good (80/100). Excellent GTAW/EBW/laser weldability but only under high-purity argon trailing shield, glove box or vacuum — any O/N/H pickup above ~500 °C embrittles the weld; no filler needed for thin sections and no post-weld heat treatment other than vacuum stress relief.
What surface finishes work on R04261-CW?
Pickle in HNO3/HF mixtures to remove oxide (short exposure — HF attacks Nb), electropolish for high-purity or UHV surfaces, or anodise to a coloured Nb2O5 film; for service in air above ~400 °C an aluminide or silicide coating is mandatory.
Can R04261-CW be formed, bent or molded?
Very ductile cold: deep draws, spins, bends to tight radii at room temperature with lubricated tooling (avoid iron pickup); anneal 1100–1250 °C in vacuum between heavy reductions.
What is the maximum service temperature of R04261-CW?
R04261-CW is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between R04261 Annealed and R04261-CW?
Annealed is the default condition — standard stocked condition for sheet, plate, bar and tube — maximum ductility for forming, welding and deep drawing. CW: highest room-temperature strength and hardness for wire, thin strip and springs, but limited formability and it recrystallizes above ~1100 °C. Yield strength is 200 MPa in Annealed versus 500 MPa in CW.
Sources
- ASTM B393 — Niobium and Niobium Alloy Strip, Sheet, and Plate (Type 4, R04261) — ASTM International (2018)
- ASTM B392 — Niobium and Niobium Alloy Bar, Rod, and Wire — ASTM International (2020)
- ASTM B391 — Niobium and Niobium Alloy Ingots — ASTM International (2018)
- ASTM B394 — Niobium and Niobium Alloy Seamless and Welded Tubes — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (refractory metals) — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (niobium and tantalum) — ASM International (2005)
- Niobium and Nb-1Zr mill product datasheets — refractory-metal producers (e.g. H.C. Starck / Ningxia Orient Tantalum) (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.