Refractory Metal Nuclear Grade Hafnium (R1) Cast
Grade
UNS R01001 · ASTM B737
Cast = as cast
Melting-stock condition (consumable-arc or electron-beam ingot) sold for onward forging, rolling or alloy additions.
Values for the Cast condition
Other Nuclear Grade Hafnium (R1) tempers and conditions
Nuclear Grade Hafnium (R1) is listed in 5 conditions; see the grade overview at Nuclear Grade Hafnium (R1).
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
CastThis page As cast | Melting-stock condition (consumable-arc or electron-beam ingot) sold for onward forging, rolling or alloy additions. | 220 | 400 | 16 | 150 HB | 5.2 % IACS |
ANNDefault Annealed | Standard stocked condition for control-rod bar, plate and sheet; best ductility and dimensional stability under irradiation. | 240 | 445 | 25 | 160 HB | — |
Hot Worked | Mill condition for heavy bar, billet and plate that will be machined or re-annealed by the fabricator. | 285 | 480 | 20 | 175 HB | 5.2 % IACS |
Cold Worked + Stress Relieved | Compromise condition: keeps most cold-work strength while removing residual stress for tight-tolerance machined rod and tubing. | 480 | 600 | 12 | 19 HRC | 5 % IACS |
Cold worked | Pick when higher strength and straightness are needed in wire, thin strip or tubing and no post-weld ductility is required. | 550 | 650 | 8 | 22 HRC | 5 % IACS |
What is Nuclear Grade Hafnium (R1) Cast?
Nuclear Grade Hafnium (R1) Cast is Nuclear Grade Hafnium (R1) in the Cast grade — melting-stock condition (consumable-arc or electron-beam ingot) sold for onward forging, rolling or alloy additions. Nuclear Grade Hafnium (R1) Cast has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 81% of refractory metal grades. Elongation at break is 16% and the elastic modulus is 138 GPa (20 Msi). Nuclear Grade Hafnium (R1) Cast has a density of 13.31 g/cm³ (0.481 lb/in³), heavier than 77% of refractory metal grades. It melts at 2,233°C (4,051 °F). ANN is the default condition FabDigit quotes; Cast is available on request or by drawing note.
Limitations
- Low strength — 220 MPa (31.9 ksi), worse than 81% of refractory metal grades
- Heavy — 13.31 g/cm³ (0.481 lb/in³), worse than 77% of refractory metal grades
- High embodied carbon — 95 kg CO₂/kg, worse than 75% of refractory metal grades
Nuclear Grade Hafnium (R1) Cast properties
Typical room-temperature values for Nuclear Grade Hafnium (R1) Cast; 22 are specific to this condition. Other listed values are Nuclear Grade Hafnium (R1) reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
Nuclear Grade Hafnium (R1) Cast has a density of 13.31 g/cm³ (0.481 lb/in³), heavier than 77% of refractory metal grades. It melts at 2,233°C (4,051 °F).
Mechanical12
Nuclear Grade Hafnium (R1) Cast has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 81% of refractory metal grades. Elongation at break is 16% and the elastic modulus is 138 GPa (20 Msi).
Thermal6
Nuclear Grade Hafnium (R1) Cast is rated for continuous service to 400°C (752 °F). It conducts heat at 23 W/m·K (13.3 BTU/hr·ft·°F), worse than 61% of refractory metal grades. Thermal expansion is 5.9 µm/m·K (3.28 µin/in·°F).
Electrical3
Nuclear Grade Hafnium (R1) Cast conducts electricity at 5.2 % IACS, worse than 55% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 52% of refractory metal grades.
Sustainability2
Producing a kilogram of Nuclear Grade Hafnium (R1) Cast takes about 1,400 MJ of energy and emits 95 kg of CO₂ — more than 67% of refractory metal grades.
Manufacturability8
Nuclear Grade Hafnium (R1) Cast's machinability is poor (28/100, worse than 58% of refractory metal grades); weldability good (55/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Nuclear Grade Hafnium (R1) Cast
Is Nuclear Grade Hafnium (R1) easy to machine?
Machine like reactor-grade zirconium: slow speeds, heavy positive-rake sharp carbide tools, deep cuts and flood coolant — fine chips and dust are pyrophoric and must be kept wet and collected separately.
Can Nuclear Grade Hafnium (R1) be welded?
GTAW, plasma or EBW in a purged chamber or with full trailing/back shielding of high-purity argon or helium; keep oxygen, nitrogen and hydrogen out or the weld embrittles — bright silvery bead is the acceptance clue.
Can Nuclear Grade Hafnium (R1) be formed, bent or molded?
Bend and roll warm (150–400 °C) with generous radii because of the hcp texture; heavy reductions need intermediate vacuum anneals around 700–800 °C.
What surface finishes work on Nuclear Grade Hafnium (R1)?
Pickle in HNO₃–HF to remove oxide and forming lubricants, then rinse and passivate; avoid iron contamination and do not plate — the natural HfO₂ film is the corrosion barrier.
Nuclear Grade Hafnium (R1) 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 |
|---|---|---|
| Zrreactor-grade R1 limit; some buyers specify ≤2.0 % | ≤ 4.5 | 2 |
| O | ≤ 0.13 | 0.08 |
| C | ≤ 0.02 | 0.01 |
| N | ≤ 0.01 | 0 |
| H25 ppm max | ≤ 0 | 0 |
| Feoften specified with Cr as Fe+Cr | ≤ 0.08 | 0.03 |
| Cr | ≤ 0.01 | — |
| Ni | ≤ 0.01 | — |
| Ti | ≤ 0.01 | — |
| Al | ≤ 0.01 | — |
| Cu | ≤ 0.01 | — |
| Mo | ≤ 0.01 | — |
| Nb | ≤ 0.01 | — |
| W | ≤ 0.01 | — |
| U3 ppm max, nuclear purity | ≤ 3×10⁻⁴ | — |
| Hfbalance, hafnium plus permitted zirconium | balance | — |
Nuclear Grade Hafnium (R1) Cast — frequently asked
What is Nuclear Grade Hafnium (R1) Cast used for?
Nuclear Grade Hafnium (R1) Cast is typically used for reactor control rods, neutron absorber components, nuclear submarine reactor internals and control rod cladding. In short: strong neutron absorber metal; nuclear-purity, low-zirconium hafnium; control rod reference grade.
What is the yield strength of Nuclear Grade Hafnium (R1) Cast?
Nuclear Grade Hafnium (R1) Cast has a typical yield strength of 220 MPa (31.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 81% of refractory metal grades. Strength varies by condition: see the 5 listed tempers.
Is Nuclear Grade Hafnium (R1) Cast easy to machine?
Not especially — machinability is rated poor (28/100, worse than 58% of refractory metal grades). Machine like reactor-grade zirconium: slow speeds, heavy positive-rake sharp carbide tools, deep cuts and flood coolant — fine chips and dust are pyrophoric and must be kept wet and collected separately.
Can Nuclear Grade Hafnium (R1) Cast be welded?
Yes — weldability is rated good (55/100). GTAW, plasma or EBW in a purged chamber or with full trailing/back shielding of high-purity argon or helium; keep oxygen, nitrogen and hydrogen out or the weld embrittles — bright silvery bead is the acceptance clue.
What surface finishes work on Nuclear Grade Hafnium (R1) Cast?
Pickle in HNO₃–HF to remove oxide and forming lubricants, then rinse and passivate; avoid iron contamination and do not plate — the natural HfO₂ film is the corrosion barrier.
Can Nuclear Grade Hafnium (R1) Cast be formed, bent or molded?
Bend and roll warm (150–400 °C) with generous radii because of the hcp texture; heavy reductions need intermediate vacuum anneals around 700–800 °C.
What is the maximum service temperature of Nuclear Grade Hafnium (R1) Cast?
Nuclear Grade Hafnium (R1) Cast is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Nuclear Grade Hafnium (R1)-ANN and Nuclear Grade Hafnium (R1)-CW?
ANN is the default condition — standard stocked condition for control-rod bar, plate and sheet; best ductility and dimensional stability under irradiation. CW: pick when higher strength and straightness are needed in wire, thin strip or tubing and no post-weld ductility is required. Yield strength is 240 MPa in ANN versus 550 MPa in CW.
Sources
- ASTM B737 — Hafnium and Hafnium Alloy Bar, Rod and Wire — ASTM International (2021)
- ASTM B776 — Hafnium and Hafnium Alloy Strip, Sheet and Plate — ASTM International (2021)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Hafnium metal — reactor grade technical data — ATI Wah Chang (2018)
- CRC Handbook of Chemistry and Physics — elemental properties of hafnium — CRC Press (2022)
- Hafnium metal price series / — USGS MCS & SMM (2025)
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.