R60804 is Zircaloy-4 (Zr-1.5Sn-Fe-Cr), a nuclear-grade zirconium alloy. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
Zirconium nuclear alloys combine a very low thermal-neutron-capture cross-section with good corrosion resistance in high-temperature reactor water and steam. R60804 is Zircaloy-4 (Zr-1.5Sn-Fe-Cr); the tin, iron and chromium (and, in Zircaloy-2, nickel) additions improve corrosion resistance and strength while the controlled low hafnium content preserves neutron economy. It is used principally as fuel cladding and core structural material in pressurised-water reactors (PWR), and is supplied in the annealed condition.
Typical applications include pressurised-water-reactor (PWR) fuel cladding and core structural components.
| Property | Value | Unit |
|---|---|---|
| Density | 6.51 | g/cm³ |
| Melting point | 1852 | °C |
| Elastic modulus | 99 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 5.9 | µm/m·°C |
| Thermal conductivity (20 °C) | 22 | W/m·K |
| Specific heat (20 °C) | 285 | J/kg·K |
| Structure | Hexagonal close-packed (alpha) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Zirconium | Zr | Balance | — | Base element |
| Tin | Sn | 1.20 | 1.70 | Strength, corrosion resistance |
| Iron | Fe | 0.18 | 0.24 | Corrosion resistance |
| Chromium | Cr | 0.07 | 0.13 | Corrosion resistance |
| Oxygen | O | — | 0.16 | Interstitial; strength |
| Nickel | Ni | — | 0.007 | Restricted (Zircaloy-4) |
| Hafnium | Hf | — | 0.010 | Controlled low (nuclear) |
Annealed condition, typical values for ASTM B350 UNS R60804.
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (UTS) | ≥413 MPa (60 ksi) |
| Annealed | 0.2% yield strength | ≥241 MPa (35 ksi) |
| Annealed | Elongation at break | ≥16 % |
| Cold-worked | Tensile strength (UTS) | higher; less ductile |
| — | Elastic modulus | 99 GPa |
Confirm against the mill test report. Strength depends on oxygen content and condition.
| Environment | Performance | Notes |
|---|---|---|
| Reactor coolant water / steam | Excellent | Low corrosion + low neutron capture |
| High-temperature water (288–360 °C) | Excellent | Fuel-cladding service |
| Sulfuric acid (≤70%) | Excellent | Resistant; attacked at high conc. |
| Strong alkalis | Excellent | Resists hot caustic |
| Ferric / cupric chlorides, aqua regia | Poor | Attacked; also HF |
Zirconium offers outstanding resistance to hydrochloric and nitric acids, hot caustic and many organic acids through a self-healing oxide film, but is attacked by hydrofluoric acid, ferric and cupric chlorides, wet chlorine and aqua regia.
A reactive metal; not hardenable by precipitation. Properties are governed by working and annealing.
Anneal Anneal in vacuum or a protective atmosphere at approximately 540–815 °C to recrystallise and restore ductility after cold work. Avoid oxygen, nitrogen and hydrogen pickup, which embrittle the metal; pickling removes surface contamination.
Excellent weldability by inert-gas processes; the weld and hot metal must be fully shielded from air (trailing shields, backing gas or chambers), because oxygen, nitrogen and hydrogen pickup cause embrittlement.
| Welding Process | Applicability | Notes |
|---|---|---|
| GTAW / TIG | Excellent | Full inert shielding / trailing shield |
| GMAW / MIG | Good | Matching filler |
| EBW / plasma | Good | Vacuum or high-purity shielding |
Weld under full inert-gas shielding with clean surfaces; a bright, silvery weld indicates good shielding, while colours indicate contamination.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Fair; sharp tooling, slow speeds, heavy feeds |
| Caution | Fine chips/dust are pyrophoric — manage swarf, flood coolant |
| Coolant | Ample non-chlorinated coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Good; ductile when annealed |
| Hot forming | Performed warm/hot under protection from oxidation |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Nuclear fuel | Fuel-rod cladding tubes | Low neutron capture + corrosion resistance |
| Reactor core | Structural grids, channels | Strength + corrosion in coolant |
| pressurised-water reactors (PWR) | Core components | Neutron economy + durability |
| Power generation | Reactor internals | High-temperature water resistance |
| Product Form | ASTM Standard | Notes |
|---|---|---|
| Strip, sheet and plate | ASTM B352 | UNS R60804 |
| Bar and wire | ASTM B351 | UNS R60804 |
| Seamless and welded tube (cladding) | ASTM B353 | UNS R60804 |
| Material designation | UNS R60804 | Zircaloy-4 (Zr-1.5Sn-Fe-Cr) |
Zircaloy-4 (Zircaloy-4 (Zr-1.5Sn-Fe-Cr)). UNS R60804.
| UNS | Composition | Grade | Best Used For |
|---|---|---|---|
| R60804 | Zircaloy-4 (Zr-Sn-Fe-Cr) | Nuclear | PWR fuel cladding and core structural material |
| R60802 | Zircaloy-2 (Zr-Sn-Fe-Cr-Ni) | Nuclear | BWR fuel cladding (with nickel) |
| R60001 | Nuclear-grade Zr | Nuclear | Nuclear-grade unalloyed zirconium |
| R60702 | Unalloyed Zr | Industrial | Industrial zirconium; chemical service |
| R60705 | Zr-2.5Nb | Industrial | Higher-strength zirconium-niobium alloy |




