Alloy Overview
Grade 702 is a commercially pure zirconium grade with a minimum zirconium content of 99.2% (including a maximum of 4.5% hafnium). It contains controlled levels of iron (Fe), chromium (Cr), and oxygen (O), retaining zirconium’s inherent corrosion resistance while offering balanced mechanical properties. This grade is valued for its formability and reliability in aggressive environments.
Chemical Composition (Weight %)
| Component | Chemical Composition (Weight %) |
| Zr (Zr + Hf) | Min 99.2 (balance) |
| Fe + Cr | 0.2 |
| Hf | Max 4.5 |
| O | 0.16 |
Material Notes:
The zirconium content includes hafnium content, with hafnium controlled at a maximum of 4.5%.
Physical Properties
| Property | Metric | English |
| Density | 6.5 g/cc | 0.235 lb/in³ |
Mechanical Properties
| Property | Metric | English | Notes |
| Hardness (Rockwell A) | 49 | 49 | Estimated from Vickers |
| Hardness (Rockwell B) | 78 | 78 | Estimated from Vickers |
| Hardness (Vickers) | 150 | 150 | Annealed sample |
| Tensile Strength (Ultimate) | Min 379 MPa | Min 55,000 psi | |
| Tensile Strength (Yield, 0.2%) | Min 207 MPa | Min 30,000 psi | 0.2% offset |
| Elongation at Break | 16% | 16% | Measured in 50 mm |
| Modulus of Elasticity | 99.3 GPa | 14,400 ksi | |
| Poisson’s Ratio | 0.35 | 0.35 | |
| Shear Modulus | 36.2 GPa | 5,250 ksi | |
| Fatigue Strength (Notched, 5×10⁵ cycles) | 125 MPa | 18,100 psi | 5×10⁵ cycles |
| Fatigue Strength (Unnotched, 3×10⁷ cycles) | 145 MPa | 21,000 psi | 3×10⁷ cycles |
| Fatigue Strength (Unnotched, 5×10⁵ cycles) | 175 MPa | 25,400 psi | 5×10³ cycles |
| Fatigue Strength (Notched, 3×10⁷ cycles) | 60 MPa | 8,700 psi | 3×10⁷ cycles |
Electrical & Magnetic Properties
| Property | Metric | English | Notes |
| Electrical Resistivity | 3.97e-005 ohm-cm | 3.97e-005 ohm-cm | Temp coefficient: 0.0044/°C at 20°C |
| Magnetic Susceptibility | 1.34e-006 cgs/g | 1.34e-006 cgs/g | Pure Zr |
| Critical Magnetic Field Strength | 47 oersted | 47 oersted | Pure Zr |
| Critical Superconducting Temperature | 0.595 – 0.625 K | 0.595 – 0.625 K | Pure Zr |
Thermal Properties
| Property | Metric | English | Notes |
| Heat of Fusion | 250 J/g | 108 BTU/lb | |
| Linear CTE (20°C) | 5.89 μm/m-°C | 3.27 μin/in-°F | Measured at 25°C |
| Linear CTE (250°C) | 6.3 μm/m-°C | 3.5 μin/in-°F | |
| Linear CTE (500°C) | 6.9 μm/m-°C | 3.83 μin/in-°F | |
| Specific Heat Capacity | 0.285 J/g-°C | 0.0681 BTU/lb-°F | |
| Thermal Conductivity | 22 W/m-K | 153 BTU-in/hr-ft²-°F | |
| Melting Point | 1852°C | 3370°F |
Optical Properties
| Property | Metric | English | Notes |
| Emissivity (0-1) | 0.32 | 0.32 | 650 nm; unoxidized pure Zr sample; total |
Available Forms
Custom Zirconium Components
Zirconium Grade 702 Plate
Zirconium Grade 702 Sheet
Zirconium Grade 702 Bar
Zirconium Grade 702 Rod
Zirconium Grade 702 Tube
Zirconium Grade 702 Pipe
Key Features & Applications
- Corrosion Resistance: Excellent in aggressive media (e.g., acids, high-temperature water), making it ideal for chemical processing and nuclear industries.
- Formability: Balances strength and ductility, suitable for fabrication into sheets, tubes, and complex components.
- Typical Uses: Chemical processing equipment, heat exchangers, nuclear reactor cladding, and marine applications requiring corrosion resistance.
- In industrial practice, Grade 702 zirconium is commonly supplied in plate and sheet form for corrosion-resistant linings and heat exchanger components, as well as pipe and tube for fluid handling in chemical and nuclear systems. Rod and bar products are typically used for structural parts and fabrication, while foil, strip, and wire may be specified for specialized forming, joining, or assembly requirements.