Refractory Metal Zr 702
UNS R60702 · ASTM B550/B551 Grade 702
The workhorse commercially-pure zirconium grade (>99% Zr+Hf), prized for outstanding corrosion resistance to acids, alkalis and seawater; the default choice for chemical-process piping, reactors and heat exchangers.
Reference datasheet — Zr 702 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the Annealed condition
Zr 702 tempers and conditions
Zr 702 is supplied in 5 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As-welded deposit | Property basis for fabricated vessels and pipe joints welded with full inert shielding; coarse weld-metal grain lowers ductility slightly, strength matches base metal. | 280 | 450 | 18 | 165 HB | 4.3 % IACS |
AnnealedDefault recrystallization annealed (ASTM B550/B551/B523/B658 standard condition) | Default stocked condition for plate, sheet, bar, pipe and tube in chemical-process service; best ductility, formability and corrosion behaviour. | 290 | 450 | 30 | 150 HB | — |
Hot worked | Economical condition for heavy forged sections and thick plate before final annealing; slightly higher strength, coarser structure than annealed. | 330 | 480 | 25 | 165 HB | 4.3 % IACS |
Cold worked and stress relieved | Pick for cold-drawn tubing and pipe where higher strength and tight dimensional control are needed while retaining useful ductility. | 450 | 550 | 18 | 95 HRB | — |
Cold worked | Highest strength condition of Zr 702; used for fasteners, springs, wire and machined parts where ductility demands are modest. | 550 | 620 | 12 | 100 HRB | — |
What is Zr 702?
The workhorse commercially-pure zirconium grade (>99% Zr+Hf), prized for outstanding corrosion resistance to acids, alkalis and seawater; the default choice for chemical-process piping, reactors and heat exchangers. Zr 702 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). Zr 702 has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 63% of refractory metal grades. Elongation at break is 30% and the elastic modulus is 99 GPa (14.4 Msi).
What is Zr 702 used for?
- Acid plant piping
- Heat exchangers
- Chemical reactor vessels
- Nuclear-adjacent process equipment
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
- Tough — resists crack growth — 65 MPa·√m (59.2 ksi·√in), better than 80% of refractory metal grades
- Forms and bends easily — 70/100, better than 75% of refractory metal grades
Limitations
- Limited service temperature — 371°C (700 °F), worse than 87% of refractory metal grades
- Low stiffness — 99 GPa (14.4 Msi), worse than 79% of refractory metal grades
Zr 702 properties
Typical room-temperature values for Zr 702-Annealed; bars are the position among refractory metal grades.
Physical3
Zr 702 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
Zr 702 has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 63% of refractory metal grades. Elongation at break is 30% and the elastic modulus is 99 GPa (14.4 Msi).
Thermal6
Zr 702 is rated for continuous service to 371°C (700 °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 5.9 µm/m·K (3.28 µin/in·°F).
Electrical3
Zr 702 conducts electricity at 4.3 % IACS, worse than 62% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 86% of refractory metal grades.
Sustainability4
Producing a kilogram of Zr 702 takes about 1,250 MJ of energy and emits 85 kg of CO₂ — more than 52% of refractory metal grades. Typical recycled content is 15%.
Manufacturability8
Zr 702's machinability is fair (35/100, better than 81% of refractory metal grades); weldability very good (80/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the refractory metal family
Yield strength against density for every refractory metal grade FabDigit runs. Zr 702 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Zr 702
Is Zr 702 easy to machine?
Machine like a gummy austenitic stainless — sharp uncoated carbide, slow speeds, heavy positive rake, generous flood coolant; collect chips wet, fine turnings and grinding dust are pyrophoric.
Can Zr 702 be welded?
GTAW (or EB/plasma) with high-purity argon plus trailing shield and back purge; keep the weld and HAZ bright-silver — straw/blue/grey tint means oxygen pickup and must be removed.
Can Zr 702 be formed, bent or molded?
Cold forms readily at 3–5t bend radii but springs back strongly; warm forming at 200–350 °C is used for tight bends and heads, and hydrogen/oxygen pickup must be avoided in any heating.
Zr 702 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 |
|---|---|---|
| Hfmax per ASTM B550/B551 | ≤ 4.5 | 2 |
| Fe+Cr | ≤ 0.2 | 0.1 |
| Oprincipal strengthening interstitial | ≤ 0.16 | 0.1 |
| C | ≤ 0.05 | 0.02 |
| N | ≤ 0.03 | 0.01 |
| Hhydrogen embrittlement control | ≤ 0.01 | 0 |
| Zr+HfHf is not removed in commercial grade | ≥ 99.2 (balance) |
What surface finishes work on Zr 702?
Pickle in HNO3–HF to remove oxide/contaminated layers, then descale-free passivation; can be electropolished or anodized to coloured oxide, avoid iron contamination from steel tooling.
Equivalent designations
Standards and trade names that resolve to Refractory Metal Zr 702 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R60702
- ASTM
- B550/B551 Grade 702
How much does Zr 702 cost?
Zr 702 is a high-cost refractory metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Zr 702 — frequently asked
What is Zr 702 used for?
Zr 702 is typically used for acid plant piping, heat exchangers, chemical reactor vessels and nuclear-adjacent process equipment. In short: default corrosion-service zirconium; handles hot acids and alkalis; weldable and cold formable.
What is the yield strength of Zr 702?
Zr 702 has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 63% of refractory metal grades. Strength varies by condition: see the 5 listed tempers.
Is Zr 702 easy to machine?
Not especially — machinability is rated fair (35/100, better than 81% of refractory metal grades). Machine like a gummy austenitic stainless — sharp uncoated carbide, slow speeds, heavy positive rake, generous flood coolant; collect chips wet, fine turnings and grinding dust are pyrophoric.
Can Zr 702 be welded?
Yes — weldability is rated very good (80/100). GTAW (or EB/plasma) with high-purity argon plus trailing shield and back purge; keep the weld and HAZ bright-silver — straw/blue/grey tint means oxygen pickup and must be removed.
What surface finishes work on Zr 702?
Pickle in HNO3–HF to remove oxide/contaminated layers, then descale-free passivation; can be electropolished or anodized to coloured oxide, avoid iron contamination from steel tooling.
Can Zr 702 be formed, bent or molded?
Cold forms readily at 3–5t bend radii but springs back strongly; warm forming at 200–350 °C is used for tight bends and heads, and hydrogen/oxygen pickup must be avoided in any heating.
What is the maximum service temperature of Zr 702?
Zr 702 is rated for continuous use to about 371°C (700 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Zr 702 Annealed and Zr 702-CW?
Annealed is the default condition — default stocked condition for plate, sheet, bar, pipe and tube in chemical-process service; best ductility, formability and corrosion behaviour. CW: highest strength condition of Zr 702; used for fasteners, springs, wire and machined parts where ductility demands are modest. Yield strength is 290 MPa in Annealed versus 550 MPa in CW.
How much does Zr 702 cost?
Zr 702 is a high-cost refractory metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B551/B551M — Zirconium and Zirconium Alloy Strip, Sheet, and Plate — ASTM International (2019)
- ASTM B550/B550M — Zirconium and Zirconium Alloy Bar and Wire — ASTM International (2020)
- ASTM B523 / B658 — Zirconium alloy seamless tube and pipe — ASTM International (2020)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys (Zirconium and Hafnium) — ASM International (1990)
- Zirconium 702 alloy data and corrosion tables — ATI (Wah Chang) (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.