Zr702 (international designation UNS R60702) is a commercially pure alpha-phase zirconium grade that complies with the ASTM B550/B550M standard for zirconium and zirconium alloy bars and wires. Thanks to its exceptional corrosion resistance, it serves as a key structural material in highly corrosive chemical processing environments.
Zr702 (international designation UNS R60702) is a commercially pure alpha-phase zirconium grade that complies with the ASTM B550/B550M standard for zirconium and zirconium alloy bars and wires. Thanks to its exceptional corrosion resistance, it serves as a key structural material in highly corrosive chemical processing environments.
The ASTM B550 standard covers three grades of zirconium and zirconium alloy bars and wires:
| Grade | UNS No. | Material Type | Typical Applications | Standards |
| Zr702 | R60702 | Unalloyed Zirconium (Commercially Pure) | Chemical equipment linings, corrosion-resistant structural components | ASTM B550/B550M、ASME SB550、GB/T 8769、GB/T 26314 |
| Zr704 | R60704 | Zirconium-Tin Alloy | Nuclear reactor cladding tubes | ASTM B550/B550M |
| Zr705 | R60705 | Zirconium-Niobium Alloy（含Nb 2.0-3.0%） | Corrosion-resistant, high-strength structural components | ASTM B550/B550M |
Specifications:
| Parameter | Specification Range |
| Diameter/OD | Φ0.5 – Φ800 mm |
| Length | 50 – 6000 mm（customizable） |
| Density | 6.51 g/cm³ |
| Supply Condition | nnealed (M), Hot-worked (R), Cold-worked (Y) |
| Surface Condition | Polished, Turned, Forged, Rolled, Black (as-processed) |
Dimensional Tolerance Reference:
Cold-worked round bars (diameter ≤25mm): tolerance ±0.05mm
Precision ground bars: h6 or h7 tolerance grades available (e.g., Φ20mm h6 tolerance is 0/-0.013mm); surface roughness Ra ≤1.6μm
Zr702 exhibits excellent performance in the following media:
Hydrochloric acid (20%, boiling point): Corrosion rate < 0.02 mm/a
Sulfuric acid (20%, boiling): Service life > 10 years (1,000 times that of 316 stainless steel)
Acetic acid/hydroiodic acid/iodomethane (methanol carbonylation): Virtually no corrosion; can replace tantalum at 60% lower cost
Strong alkaline solutions (sodium hydroxide, etc.): Corrosion resistance comparable to nickel
High-temperature steam, chloride solutions, alkaline media: Excellent corrosion resistance
| Industry Sector | Typical Application Scenarios | Product Forms |
| Chemical/Petrochemical | cetic acid reactor linings, methanol carbonylation tower internals, HCl condenser heat exchanger tubesheets/tube bundles, sulfuric acid dilution coolers | Bars, tubes, plates, forgings |
| Chlor-alkali Industry | Caustic soda pump shafts, HCl pipeline flanges, high-temperature/high-pressure valve stems, agitator blades | Bars (machined shafts), flanges |
| Fine Chemicals & Pharmaceuticals | High-pressure reactor liners, corrosion-resistant sampling tubes, aseptic piping systems | Bars, tubes, lining plates |
| Nuclear Industry | Nuclear reactor structural materials | Bars, tubes, forgings |
| Aerospace | Corrosion-resistant structural components | Bars, precision machined parts |
| Electronics/Vacuum Coating | Zirconium targets, structural components for the electronics industry | Bars, plate targets |
Chemical Composition (ASTM B550 Standard Requirements)
Zr702 (UNS R60702) is commercially pure zirconium, based on high-purity zirconium with strictly controlled impurity element content:
| Element | Standard Requirement (wt%) | Remarks |
| Zr + Hf | ≥ 99.2% | Matrix |
| Hf | ≤ 4.5% | Hafnium is an associated element |
| Fe + Cr | ≤ 0.20% | — |
| O | 0.10 – 0.16% | Interstitial element |
| C | ≤ 0.05% | — |
| N | ≤ 0.025% | Interstitial element |
| H | ≤ 0.005% | Strictly controlled to prevent hydrogen |
| Property Indicator | ASTMB550 Requirement | Typical Measured Value |
| Tensile Strength（Rm） | ≥ 379 – 380 MPa | ≥ 380 MPa |
| Yield Strength（Rp0.2） | ≥ 207 – 240 MPa | ≥ 240 MPa |
| Elongation（A50mm） | ≥ 16% | ≥ 20% |
| Hardness | — | HV 120–150 |
| Melting Point | 1852℃ | — |
| Density | 6.51 g/cm³ | — |
Comparison of Full Life-Cycle Costs with Other Common Industrial Metals
| Comparison Criteria | Zr702 Zirconium Bar | 316L Stainless Steel | Hastelloy（C-276） | Tantalum |
| Initial Material Cost | Moderately High | Low | High | Extremely High |
| Density（g/cm³） | 6.51 | 7.98 | 8.89 | 16.6 |
| Equipment Weight | Baseline | +23% | +37% | +155% |
| Hydrochloric Acid Resistance (Boiling) | Excellent（＜0.02 mm/a） | Poor (Rapid Corrosion) | Excellent | Excellent |
| Sulfuric Acid Resistance (Boiling) | Excellent (Service Life >10 Years) | Poor | Excellent | Excellent |
| Stress Corrosion Resistance | Immune | Susceptible | Good | Immune |
| Maintenance/Replacement Cost | Extremely Low | High (Frequent Replacement) | Moderate | Extremely Low |
| Total Lifecycle Cost | Low | High | Moderately High | Extremely High |
Key Conclusions:
With these advantages, Zr702 zirconium rods are widely applicable in harsh environments with extremely high corrosion requirements, such as in the chemical, petrochemical, pharmaceutical, chlor-alkali, and nuclear industries.
| Standard No. | Scope of Application |
| ASTM B550/B550M | Zirconium and zirconium alloy bars and wires |
| ASME SB550 | Zirconium bars for pressure vessels |
| GB/T 8769 | National standard for zirconium and zirconium alloy bars |
| GB/T 26314 | Zirconium and zirconium alloy forgings |
| Inspection | Category Test Method | Purpose |
| Chemical Composition | Spectroscopic analysis | Verify elemental content meets standards |
| Mechanical Properties | Tensile test | Tensile strength, yield strength, elongation |
| Non-destructive Testing | ltrasonic Testing (UT), Eddy Current Testing (ET) | Detection of internal defects |
| Hydrogen Content | Specialized test | Prevention of hydrogen embrittlement |
| Grain Size | Rating (ASTM Grade 6–7) | Microstructural uniformity |
| Hydrostatic/Airtightness | Hydrostatic test, airtightness test | Sealing integrity (applicable to tubing) |
| Dimensional Accuracy | Dimensional measurement | Diameter, length, straightness |
Quality Commitment
Company Advantages
Q1: What are the differences between Zr702 and Zr705? How to choose?
A: Zr702 is industrial pure zirconium (UNS R60702), with better corrosion resistance and lower cost; Zr705 is zirconium-niobium alloy (UNS R60705), with higher strength. Generally, Zr702 is preferred in strong corrosive chemical environments; Zr705 can be selected for higher strength corrosion-resistant structural components.
Q2: What is the standard delivery state of the Zr702 zirconium rod?
A: The default delivery state is recrystallization annealed state (M), which has the best plasticity and is convenient for subsequent bending, welding, etc. Processing can also be provided in hot processed state (R) or cold processed state (Y) upon request.
Q3: Can Zr702 zirconium rods be welded?
A: Yes. Zr702 has good weldability. TIG welding (with pure Ar gas purity ≥ 99.999%) or electron beam welding is recommended. After welding, stress relief annealing at 600℃ is recommended. Direct welding in the air is strictly prohibited.
Q4: In which media is Zr702 not corrosion-resistant?
A: Zr702 is not corrosion-resistant in hydrofluoric acid (HF) and free fluoride ions. Isolation measures or composite linings should be taken in these media.
Q5: What is the minimum order quantity? Can small batch samples be ordered?
A: Small batch samples can be dispatched. Zero cutting is supported. The specific order quantity can be consulted.
Q6: What are the machining precautions for zirconium rods?
A: It is recommended to use carbide or TiAlN coated cutting tools, with low rotational speed and high-pressure coolant. Avoid cutting temperatures exceeding 300℃ (to prevent surface hydrogen absorption/oxidation).
Q7: Does the product provide material certificates?
A: Yes. Each batch of products comes with a material certificate, and a complete set of testing reports including chemical composition, mechanical properties, and non-destructive testing can be provided.
