Refractory Metal Zr 702 Annealed
Temper · default condition
UNS R60702 · ASTM B550/B551 Grade 702
Default stocked condition for plate, sheet, bar, pipe and tube in chemical-process service; best ductility, formability and corrosion behaviour.
Values for the Annealed condition
Other Zr 702 tempers and conditions
Zr 702 is listed in 5 conditions; see the grade overview at Zr 702.
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 |
AnnealedDefaultThis page 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 Annealed?
Zr 702 Annealed is Zr 702 in the Annealed temper — default stocked condition for plate, sheet, bar, pipe and tube in chemical-process service; best ductility, formability and corrosion behaviour. Zr 702 Annealed 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). Zr 702 Annealed 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).
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 Annealed properties
Typical room-temperature values for Zr 702 Annealed; 14 are specific to this condition. Other listed values are Zr 702 reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
Zr 702 Annealed 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 Annealed 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 Annealed 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 Annealed 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 Annealed 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 Annealed'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. Confirm any required mill or lot documentation when quoting.
Working with Zr 702 Annealed
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.
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.
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) | — |
Zr 702 Annealed — frequently asked
What is Zr 702 Annealed used for?
Zr 702 Annealed 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 Annealed?
Zr 702 Annealed 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 Annealed 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 Annealed 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 Annealed?
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 Annealed 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 Annealed?
Zr 702 Annealed 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.