Refractory Metal Zr 705C
ASTM B752 Grade 705C
Zr 705C is the cast form of the niobium-bearing Zr 705 chemistry, ordered to ASTM B752 Grade 705C (UNS R60705) in as-cast (F), HIP or annealed condition.
Reference datasheet — Zr 705C 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 F condition
Zr 705C tempers and conditions
Zr 705C is supplied in 3 conditions, soft to hard. F is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Use after heavy weld repair or when dimensional stability and maximum ductility outrank peak strength. | 355 | 470 | 17 | 175 HB | 3.2 % IACS |
FDefault As fabricated | Standard supply condition for pressure-containing zirconium castings; highest as-supplied strength. | 386 | 495 | 13 | 13 HRC | 3.1 % IACS |
Hot isostatic pressed | Choose when internal porosity must be closed for radiographic acceptance, fatigue duty or thin-wall pressure parts. | 395 | 510 | 16 | 13 HRC | 3.1 % IACS |
What is Zr 705C?
Zr 705C is the cast form of the niobium-bearing Zr 705 chemistry, ordered to ASTM B752 Grade 705C (UNS R60705) in as-cast (F), HIP or annealed condition. It is the highest-strength cast zirconium grade — 386 MPa yield, 495 MPa tensile, 13% elongation, 190 HB (92 HRB) — which lets pressure-containing valve bodies and housings be produced near net shape instead of machined from wrought bar. Service is capped near 375 °C, machinability is low (score 30), and castings need generous allowances for alpha case; wrought Zr 705 is the alternative for thinner sections or higher ductility. Zr 705C has a density of 6.64 g/cm³ (0.24 lb/in³), lighter than 63% of refractory metal grades. It melts at 1,840°C (3,344 °F). Zr 705C has a yield strength of 386 MPa (56 ksi) and a tensile strength of 495 MPa (71.8 ksi) — stronger than 60% of refractory metal grades. Elongation at break is 13% and the elastic modulus is 97 GPa (14.1 Msi).
What is Zr 705C used for?
- High-strength cast valves
- Pressure-containing castings
- Chemical process equipment
Limitations
- Low stiffness — 97 GPa (14.1 Msi), worse than 91% of refractory metal grades
- Limited service temperature — 375°C (707 °F), worse than 86% of refractory metal grades
- Limited formability — 12/100, worse than 84% of refractory metal grades
- High embodied carbon — 105 kg CO₂/kg, worse than 80% of refractory metal grades
- Low electrical conductivity — 3.1 % IACS, worse than 78% of refractory metal grades
Zr 705C properties
Typical room-temperature values for Zr 705C-F; bars are the position among refractory metal grades.
Physical3
Zr 705C has a density of 6.64 g/cm³ (0.24 lb/in³), lighter than 63% of refractory metal grades. It melts at 1,840°C (3,344 °F).
Mechanical17
Zr 705C has a yield strength of 386 MPa (56 ksi) and a tensile strength of 495 MPa (71.8 ksi) — stronger than 60% of refractory metal grades. Elongation at break is 13% and the elastic modulus is 97 GPa (14.1 Msi).
Thermal6
Zr 705C is rated for continuous service to 375°C (707 °F). It conducts heat at 17.1 W/m·K (9.88 BTU/hr·ft·°F), worse than 76% of refractory metal grades. Thermal expansion is 6.3 µm/m·K (3.5 µin/in·°F).
Electrical3
Zr 705C conducts electricity at 3.1 % IACS, worse than 78% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 75% of refractory metal grades.
Sustainability4
Producing a kilogram of Zr 705C takes about 1,600 MJ of energy and emits 105 kg of CO₂ — more than 80% of refractory metal grades. Typical recycled content is 25%.
Manufacturability8
Zr 705C's machinability is poor (30/100, better than 54% of refractory metal grades); weldability good (62/100); formability not recommended (12/100).
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 705C is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Zr 705C
Is Zr 705C easy to machine?
Slow speeds, heavy positive-rake carbide, flood coolant and sharp tools to avoid galling; collect chips wet — dry fines are pyrophoric.
Can Zr 705C be welded?
GTAW with high-purity argon/helium, trailing shield or chamber; keep O/N/H pickup low and weld only clean, ground surfaces — weld repair of castings is allowed by B752 with subsequent stress relief.
Can Zr 705C be formed, bent or molded?
Cast only, by vacuum/skull induction melting into rammed graphite molds; large machining allowances and generous fillets needed because of low fluidity and alpha-case surface layer.
Zr 705C 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 |
|---|---|---|
| Nbcolumbium, primary strengthener | 2 – 3 | 2.5 |
| Hfreactor-grade Hf not separated in industrial Zr | ≤ 4.5 | 2 |
| Fe+Cr | ≤ 0.2 | 0.1 |
| O | ≤ 0.18 | 0.12 |
| C | ≤ 0.05 | 0.02 |
| N | ≤ 0.03 | 0.01 |
| H | ≤ 0.01 | 0 |
| ZrZr + Hf ≥ 95.5 % min | balance |
What surface finishes work on Zr 705C?
Grit-blast then acid pickle (HNO3/HF) to remove alpha case and mold reaction layer; passive ZrO2 film gives the corrosion resistance — no plating or painting required, polishing optional.
Equivalent designations
Standards and trade names that resolve to Refractory Metal Zr 705C in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B752 Grade 705C
- Similar grades
- R60705
How much does Zr 705C cost?
Zr 705C 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 705C — frequently asked
What is Zr 705C used for?
Zr 705C is typically used for high-strength cast valves, pressure-containing castings and chemical process equipment. In short: highest-strength cast zirconium; nb-alloyed casting grade; ASTM B752 pressure castings.
What is the yield strength of Zr 705C?
Zr 705C has a typical yield strength of 386 MPa (56 ksi) and a tensile strength of 495 MPa (71.8 ksi) — stronger than 60% of refractory metal grades. Strength varies by condition: see the 3 listed tempers.
Is Zr 705C easy to machine?
Not especially — machinability is rated poor (30/100, better than 54% of refractory metal grades). Slow speeds, heavy positive-rake carbide, flood coolant and sharp tools to avoid galling; collect chips wet — dry fines are pyrophoric.
Can Zr 705C be welded?
Yes — weldability is rated good (62/100). GTAW with high-purity argon/helium, trailing shield or chamber; keep O/N/H pickup low and weld only clean, ground surfaces — weld repair of castings is allowed by B752 with subsequent stress relief.
What surface finishes work on Zr 705C?
Grit-blast then acid pickle (HNO3/HF) to remove alpha case and mold reaction layer; passive ZrO2 film gives the corrosion resistance — no plating or painting required, polishing optional.
Can Zr 705C be formed, bent or molded?
Cast only, by vacuum/skull induction melting into rammed graphite molds; large machining allowances and generous fillets needed because of low fluidity and alpha-case surface layer.
What is the maximum service temperature of Zr 705C?
Zr 705C is rated for continuous use to about 375°C (707 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Zr 705C-F and Zr 705C-ANN?
F is the default condition — standard supply condition for pressure-containing zirconium castings; highest as-supplied strength. ANN: use after heavy weld repair or when dimensional stability and maximum ductility outrank peak strength. Yield strength is 386 MPa in F versus 355 MPa in ANN.
How much does Zr 705C cost?
Zr 705C 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 B752 — Standard Specification for Castings, Zirconium-Base, Corrosion Resistant, for General Application — ASTM International (2020)
- ASTM B551/B551M — Zirconium and Zirconium Alloy Strip, Sheet and Plate (R60705) — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Zirconium and Hafnium) — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Zirconium) — ASM International (2005)
- Zirconium Alloy 705 (R60705) technical data — 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.