Refractory Metal Zircaloy-2 PRXA
Heat-treated state
UNS R60802 · ASTM B350/B811
PRXA = partially recrystallized annealed
Intermediate anneal used on strip/tube when a balance of strength, creep resistance and ductility is wanted.
Values for the PRXA condition
Other Zircaloy-2 tempers and conditions
Zircaloy-2 is listed in 6 conditions; see the grade overview at Zircaloy-2.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
RXADefault Recrystallization annealed | Standard stocked condition for plate, sheet, strip and bar (ASTM B351/B352); best ductility and formability, used where creep is not the driver. | 320 | 490 | 27 | 180 HB | — |
As hot worked | Mill condition for heavy bar, billet and forgings before final anneal; properties similar to annealed but with more scatter and coarser texture. | 340 | 500 | 22 | 185 HB | 2.3 % IACS |
Β-quenched | Used to refine and homogenize the Fe/Cr/Ni second-phase particles for improved uniform-corrosion and nodular-corrosion behaviour in BWR water. | 350 | 540 | 18 | 200 HB | 2.1 % IACS |
PRXAThis page Partially recrystallized annealed | Intermediate anneal used on strip/tube when a balance of strength, creep resistance and ductility is wanted. | 420 | 550 | 20 | 196 HB | 2.3 % IACS |
Cold worked and stress-relief annealed | Classic cladding/pressure-tube condition per ASTM B811: retains cold-work strength and creep resistance with acceptable ductility. | 500 | 610 | 15 | 96 HRB | — |
Cold worked | Maximum strength/stiffness in tube and strip before any relief anneal; low ductility and high residual stress, normally an intermediate mill state. | 620 | 700 | 9 | 23 HRC | 2.2 % IACS |
What is Zircaloy-2 PRXA?
Zircaloy-2 PRXA is Zircaloy-2 heat treated to PRXA — intermediate anneal used on strip/tube when a balance of strength, creep resistance and ductility is wanted. Zircaloy-2 PRXA has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 66% of refractory metal grades. Elongation at break is 20% and the elastic modulus is 97 GPa (14.1 Msi). Zircaloy-2 PRXA has a density of 6.56 g/cm³ (0.237 lb/in³), lighter than 71% of refractory metal grades. It melts at 1,760°C (3,200 °F). RXA is the default condition FabDigit quotes; PRXA is available on request or by drawing note.
Limitations
- Poor heat conductor — 13.5 W/m·K (7.8 BTU/hr·ft·°F), worse than 93% of refractory metal grades
- Low stiffness — 97 GPa (14.1 Msi), worse than 91% of refractory metal grades
- Low electrical conductivity — 2.3 % IACS, worse than 90% of refractory metal grades
Zircaloy-2 PRXA properties
Typical room-temperature values for Zircaloy-2 PRXA; 22 are specific to this condition. Other listed values are Zircaloy-2 reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
Zircaloy-2 PRXA has a density of 6.56 g/cm³ (0.237 lb/in³), lighter than 71% of refractory metal grades. It melts at 1,760°C (3,200 °F).
Mechanical16
Zircaloy-2 PRXA has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 66% of refractory metal grades. Elongation at break is 20% and the elastic modulus is 97 GPa (14.1 Msi).
Thermal6
Zircaloy-2 PRXA is rated for continuous service to 400°C (752 °F). It conducts heat at 13.5 W/m·K (7.8 BTU/hr·ft·°F), worse than 93% of refractory metal grades. Thermal expansion is 6 µm/m·K (3.33 µin/in·°F).
Electrical3
Zircaloy-2 PRXA conducts electricity at 2.3 % IACS, worse than 90% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 75% of refractory metal grades.
Sustainability3
Producing a kilogram of Zircaloy-2 PRXA takes about 1,300 MJ of energy and emits 85 kg of CO₂ — more than 57% of refractory metal grades. Typical recycled content is 5%.
Manufacturability8
Zircaloy-2 PRXA's machinability is poor (33/100, better than 71% of refractory metal grades); weldability good (68/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Zircaloy-2 PRXA
Is Zircaloy-2 easy to machine?
Machine like a gummy austenitic stainless: sharp positive-rake carbide, heavy flood coolant, slow speed / generous feed to avoid galling and work-hardening — and manage fine chips and swarf as a fire hazard (never let dust accumulate, no water on a Zr fire).
Can Zircaloy-2 be welded?
GTAW, plasma or EB weld with high-purity argon/helium plus trailing shield and back purge (or vacuum); keep O, N, C and H pickup low, clean/pickle before welding, no filler contamination — discoloured (straw/blue-grey) welds must be cut out.
Can Zircaloy-2 be formed, bent or molded?
Cold roll, pilger and bend readily in the annealed state (bend radius ≥2–3 t, watch strong hcp texture and springback); warm form at 200–400 °C for tight radii, and always intermediate-anneal/stress-relieve heavily cold-worked tube.
What surface finishes work on Zircaloy-2?
Pickle in HNO3-HF and rinse to restore the passive oxide (also removes hydrogen-rich machined layer); grit blast with clean media only, avoid iron contamination, optional anodic or autoclave oxide film for appearance/galling — no electroplating in nuclear service.
Zircaloy-2 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 |
|---|---|---|
| Snsolid-solution strengthener | 1.2 – 1.7 | 1.45 |
| Fe | 0.07 – 0.2 | 0.15 |
| Cr | 0.05 – 0.15 | 0.1 |
| Nidistinguishes Zry-2 from Zry-4; raises hydrogen pickup | 0.03 – 0.08 | 0.05 |
| Fe+Cr+Nisum limit per ASTM B350 | 0.18 – 0.38 | 0.3 |
| Ocontrolled strengthener (per ASTM B811/purchase spec) | 0.09 – 0.16 | 0.12 |
| Hfnuclear-grade limit, 100 ppm max | ≤ 0.01 | — |
| C | ≤ 0.03 | — |
| N80 ppm max | ≤ 0.01 | — |
| Si | ≤ 0.01 | — |
| Al | ≤ 0.01 | — |
| Zrbalance, ~97.5 % nominal | balance | — |
Zircaloy-2 PRXA — frequently asked
What is Zircaloy-2 PRXA used for?
Zircaloy-2 PRXA is typically used for BWR fuel cladding, reactor structural components and fuel assembly hardware. In short: standard BWR cladding alloy; very low neutron absorption; nickel-bearing Zircaloy grade.
What is the yield strength of Zircaloy-2 PRXA?
Zircaloy-2 PRXA has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 66% of refractory metal grades. Strength varies by condition: see the 6 listed tempers.
Is Zircaloy-2 PRXA easy to machine?
Not especially — machinability is rated poor (33/100, better than 71% of refractory metal grades). Machine like a gummy austenitic stainless: sharp positive-rake carbide, heavy flood coolant, slow speed / generous feed to avoid galling and work-hardening — and manage fine chips and swarf as a fire hazard (never let dust accumulate, no water on a Zr fire).
Can Zircaloy-2 PRXA be welded?
Yes — weldability is rated good (68/100). GTAW, plasma or EB weld with high-purity argon/helium plus trailing shield and back purge (or vacuum); keep O, N, C and H pickup low, clean/pickle before welding, no filler contamination — discoloured (straw/blue-grey) welds must be cut out.
What surface finishes work on Zircaloy-2 PRXA?
Pickle in HNO3-HF and rinse to restore the passive oxide (also removes hydrogen-rich machined layer); grit blast with clean media only, avoid iron contamination, optional anodic or autoclave oxide film for appearance/galling — no electroplating in nuclear service.
Can Zircaloy-2 PRXA be formed, bent or molded?
Cold roll, pilger and bend readily in the annealed state (bend radius ≥2–3 t, watch strong hcp texture and springback); warm form at 200–400 °C for tight radii, and always intermediate-anneal/stress-relieve heavily cold-worked tube.
What is the maximum service temperature of Zircaloy-2 PRXA?
Zircaloy-2 PRXA 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 Zircaloy-2-RXA and Zircaloy-2-CW?
RXA is the default condition — standard stocked condition for plate, sheet, strip and bar (ASTM B351/B352); best ductility and formability, used where creep is not the driver. CW: maximum strength/stiffness in tube and strip before any relief anneal; low ductility and high residual stress, normally an intermediate mill state. Yield strength is 320 MPa in RXA versus 620 MPa in CW.
Sources
- ASTM B350/B350M — Zr and Zr-alloy ingots for nuclear application — ASTM International (2022)
- ASTM B352/B352M — Zr and Zr-alloy sheet, strip and plate for nuclear application — ASTM International (2022)
- ASTM B811 — wrought Zr-alloy seamless tubes for nuclear reactor fuel cladding — ASTM International (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Zirconium and Hafnium) — ASM International (1990)
- MATPRO / SCDAP Zircaloy thermophysical and mechanical property correlations — US NRC / INL (1993)
- Zirconium alloy mill products — corrosion, fabrication and machining guides — ATI / Western Zirconium (2020)
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.