Refractory Metal Reactor Grade Zr-ANN (Annealed)
Heat-treated state · default condition
UNS R60001 · ASTM B350 Reactor Grade
Default wrought condition for reactor-grade bar, sheet, plate and wire: maximum ductility and formability, lowest residual stress and best hydride/corrosion behaviour.
Values for the ANN condition
Other Reactor Grade Zr tempers and conditions
Reactor Grade Zr is listed in 4 conditions; see the grade overview at Reactor Grade Zr.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefaultThis page Annealed | Default wrought condition for reactor-grade bar, sheet, plate and wire: maximum ductility and formability, lowest residual stress and best hydride/corrosion behaviour. | 200 | 330 | 30 | 95 HB | 22 W/m·K |
Hot Worked | Intermediate mill condition for heavy bar, billet and plate; slightly stronger and less ductile than fully annealed, usually annealed before final service. | 250 | 380 | 25 | 110 HB | 4.1 % IACS |
Kroll-process reactor grade zirconium sponge | Buy this as melt feedstock for Zircaloy/Zr-2.5Nb ingots; quality is judged by Brinell hardness of compacted sponge plus impurity/Hf limits, not by tensile data. | — | — | — | 85 HB | 4.1 % IACS |
Cold worked and stress relieved | Choose for tube, thin strip and springy parts needing higher strength and creep resistance; ductility and formability drop and residual texture anisotropy is pronounced. | 380 | 480 | 16 | 145 HB | — |
What is Reactor Grade Zr-ANN?
Reactor Grade Zr-ANN is Reactor Grade Zr heat treated to ANN — default wrought condition for reactor-grade bar, sheet, plate and wire: maximum ductility and formability, lowest residual stress and best hydride/corrosion behaviour. Reactor Grade Zr-ANN has a yield strength of 200 MPa (29 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 87% of refractory metal grades. Elongation at break is 30% and the elastic modulus is 99 GPa (14.4 Msi). Reactor Grade Zr-ANN has a density of 6.51 g/cm³ (0.235 lb/in³), lighter than 84% of refractory metal grades. It melts at 1,852°C (3,366 °F).
Advantages
- Readily welded — 80/100, better than 92% of refractory metal grades
- Ductile — tolerates forming and impact — 30%, better than 86% of refractory metal grades
- Lightweight — 6.51 g/cm³ (0.235 lb/in³), better than 84% of refractory metal grades
- Forms and bends easily — 75/100, better than 81% of refractory metal grades
Limitations
- Limited service temperature — 350°C (662 °F), worse than 89% of refractory metal grades
- Low strength — 200 MPa (29 ksi), worse than 87% of refractory metal grades
- Low stiffness — 99 GPa (14.4 Msi), worse than 79% of refractory metal grades
Reactor Grade Zr-ANN properties
Typical room-temperature values for Reactor Grade Zr-ANN; 16 are specific to this condition. Other listed values are Reactor Grade Zr reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
Reactor Grade Zr-ANN has a density of 6.51 g/cm³ (0.235 lb/in³), lighter than 84% of refractory metal grades. It melts at 1,852°C (3,366 °F).
Mechanical16
Reactor Grade Zr-ANN has a yield strength of 200 MPa (29 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 87% of refractory metal grades. Elongation at break is 30% and the elastic modulus is 99 GPa (14.4 Msi).
Thermal6
Reactor Grade Zr-ANN is rated for continuous service to 350°C (662 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 66% of refractory metal grades. Thermal expansion is 5.8 µm/m·K (3.22 µin/in·°F).
Electrical3
Reactor Grade Zr-ANN conducts electricity at 4.1 % IACS, worse than 66% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 64% of refractory metal grades.
Sustainability4
Producing a kilogram of Reactor Grade Zr-ANN takes about 1,300 MJ of energy and emits 80 kg of CO₂ — more than 57% of refractory metal grades. Typical recycled content is 5%.
Manufacturability8
Reactor Grade Zr-ANN's machinability is fair (35/100, better than 81% of refractory metal grades); weldability very good (80/100); formability very good (75/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Reactor Grade Zr-ANN
Is Reactor Grade Zr easy to machine?
Machine like austenitic stainless but gummy: sharp positive-rake carbide or HSS tools, slow speed with heavy feed, flood coolant (water-soluble, chlorine-free) and continuous chip removal — fine chips and swarf are pyrophoric, so collect wet and never dry-grind.
Can Reactor Grade Zr be welded?
GTAW/EBW/laser only, with high-purity argon or helium chamber/trailing shield and clean pickled surfaces; oxygen, nitrogen and hydrogen pickup embrittles the weld, and bright silver bead colour is the acceptance indicator.
Can Reactor Grade Zr be formed, bent or molded?
Cold form annealed material with generous bend radii (≥3–5 t) allowing for HCP texture anisotropy and springback; warm form or forge at 700–800 °C in the alpha field, avoiding lead/chloride lubricants and iron pickup from tooling.
What surface finishes work on Reactor Grade Zr?
Nitric–hydrofluoric pickling plus grit blasting removes oxide/alpha case; autoclave pre-oxidation gives the protective black ZrO2 film, decorative anodic colours are possible, and plating/painting is rarely used.
Reactor Grade Zr 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 |
|---|---|---|
| Hfkey reactor-grade limit (<100 ppm) | ≤ 0.01 | 0.01 |
| Fe | ≤ 0.15 | 0.05 |
| Cr | ≤ 0.02 | 0.01 |
| Ocontrols strength/hardness; often reported rather than limited on sponge | ≤ 0.16 | 0.09 |
| C | ≤ 0.03 | 0.01 |
| N | ≤ 0.01 | 0 |
| H | ≤ 0 | 0 |
| Al | ≤ 0.01 | 0 |
| Si | ≤ 0.01 | 0.01 |
| Ni | ≤ 0.01 | 0 |
| Ti | ≤ 0.01 | 0 |
| Cu | ≤ 0.01 | 0 |
| Mn | ≤ 0.01 | 0 |
| Mo | ≤ 0.01 | 0 |
| W | ≤ 0.01 | 0 |
| Coactivation-sensitive | ≤ 0 | 5×10⁻⁴ |
| B≤0.5 ppm, neutron poison | ≤ 5×10⁻⁵ | 2×10⁻⁵ |
| Cd≤0.5 ppm, neutron poison | ≤ 5×10⁻⁵ | 2×10⁻⁵ |
| U (total)≤3.5 ppm | ≤ 3.5×10⁻⁴ | 1×10⁻⁴ |
| Zrbalance; typically ≥99.5 % excluding Hf | balance | — |
Reactor Grade Zr-ANN — frequently asked
What is Reactor Grade Zr-ANN used for?
Reactor Grade Zr-ANN is typically used for zircaloy feedstock, reactor internals and fuel cladding precursor material. In short: hafnium-free nuclear feedstock; lowest neutron absorption; ASTM B350 reactor purity.
What is the yield strength of Reactor Grade Zr-ANN?
Reactor Grade Zr-ANN has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 87% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.
Is Reactor Grade Zr-ANN easy to machine?
Not especially — machinability is rated fair (35/100, better than 81% of refractory metal grades). Machine like austenitic stainless but gummy: sharp positive-rake carbide or HSS tools, slow speed with heavy feed, flood coolant (water-soluble, chlorine-free) and continuous chip removal — fine chips and swarf are pyrophoric, so collect wet and never dry-grind.
Can Reactor Grade Zr-ANN be welded?
Yes — weldability is rated very good (80/100). GTAW/EBW/laser only, with high-purity argon or helium chamber/trailing shield and clean pickled surfaces; oxygen, nitrogen and hydrogen pickup embrittles the weld, and bright silver bead colour is the acceptance indicator.
What surface finishes work on Reactor Grade Zr-ANN?
Nitric–hydrofluoric pickling plus grit blasting removes oxide/alpha case; autoclave pre-oxidation gives the protective black ZrO2 film, decorative anodic colours are possible, and plating/painting is rarely used.
Can Reactor Grade Zr-ANN be formed, bent or molded?
Cold form annealed material with generous bend radii (≥3–5 t) allowing for HCP texture anisotropy and springback; warm form or forge at 700–800 °C in the alpha field, avoiding lead/chloride lubricants and iron pickup from tooling.
What is the maximum service temperature of Reactor Grade Zr-ANN?
Reactor Grade Zr-ANN is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Reactor Grade Zr-ANN and Reactor Grade Zr CWSR?
ANN is the default condition — default wrought condition for reactor-grade bar, sheet, plate and wire: maximum ductility and formability, lowest residual stress and best hydride/corrosion behaviour. CWSR: choose for tube, thin strip and springy parts needing higher strength and creep resistance; ductility and formability drop and residual texture anisotropy is pronounced. Yield strength is 200 MPa in ANN versus 380 MPa in CWSR.
Sources
- ASTM B349/B349M — Zirconium Sponge and Other Forms of Virgin Metal for Nuclear Application — ASTM International (2022)
- ASTM B350/B350M — Zirconium and Zirconium Alloy Ingots for Nuclear Application — ASTM International (2022)
- ASTM B550/B550M — Zirconium and Zirconium Alloy Bar and Wire — ASTM International (2020)
- ASTM B551/B551M — Zirconium and Zirconium Alloy Strip, Sheet, and Plate — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Zirconium and Hafnium) — ASM International (1990)
- Zirconium alloys — properties and fabrication guide — ATI (Wah Chang) (2015)
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.