Refractory Metal Zr 702C-SR (Stress relieved)
Heat-treated state
ASTM B752 Grade 702C
Pick when weld repairs or heavy machining have introduced residual stress and dimensional stability matters.
Values for the SR condition
Other Zr 702C tempers and conditions
Zr 702C is listed in 4 conditions; see the grade overview at Zr 702C.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Choose for maximum ductility and the most uniform, fully passive surface before service in aggressive acid duty. | 230 | 420 | 20 | 140 HB | 4.4 % IACS |
SRThis page Stress relieved | Pick when weld repairs or heavy machining have introduced residual stress and dimensional stability matters. | 245 | 440 | 17 | 148 HB | 4.3 % IACS |
FDefault As fabricated | Standard supply condition for corrosion-service pump and valve castings; meets B752 mechanical minima without further heat treatment. | 250 | 450 | 16 | 150 HB | — |
Hot isostatic pressed | Specify for pressure-retaining or fatigue-loaded castings where internal porosity must be closed and radiographic quality is required. | 255 | 460 | 20 | 148 HB | 4.3 % IACS |
What is Zr 702C-SR?
Zr 702C-SR is Zr 702C heat treated to SR — pick when weld repairs or heavy machining have introduced residual stress and dimensional stability matters. Zr 702C-SR has a yield strength of 245 MPa (35.5 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 72% of refractory metal grades. Elongation at break is 17% and the elastic modulus is 99 GPa (14.4 Msi). Zr 702C-SR 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). F is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Readily welded — 76/100, better than 86% of refractory metal grades
- Lightweight — 6.51 g/cm³ (0.235 lb/in³), better than 84% of refractory metal grades
Limitations
- Low stiffness — 99 GPa (14.4 Msi), worse than 79% of refractory metal grades
Zr 702C-SR properties
Typical room-temperature values for Zr 702C-SR; 22 are specific to this condition. Other listed values are Zr 702C reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
Zr 702C-SR 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).
Mechanical14
Zr 702C-SR has a yield strength of 245 MPa (35.5 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 72% of refractory metal grades. Elongation at break is 17% and the elastic modulus is 99 GPa (14.4 Msi).
Thermal6
Zr 702C-SR is rated for continuous service to 400°C (752 °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 702C-SR 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 702C-SR takes about 1,250 MJ of energy and emits 80 kg of CO₂ — more than 52% of refractory metal grades. Typical recycled content is 25%.
Manufacturability8
Zr 702C-SR's machinability is fair (36/100, better than 90% of refractory metal grades); weldability very good (76/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Zr 702C-SR
Is Zr 702C easy to machine?
Machine like austenitic stainless at low speed with heavy positive-rake sharp carbide tooling, rigid setup and flood coolant; chips and fines are pyrophoric — collect wet and never dry-grind.
Can Zr 702C be welded?
GTAW/plasma with high-purity argon or chamber welding and full backside/trailing shielding; keep O, N, H pickup low (weld must stay silver — straw or blue tint means rejectable contamination), no flux processes.
Can Zr 702C be formed, bent or molded?
Cast by vacuum/consumable-electrode skull melting into rammed graphite or investment moulds; allow generous risering and ~7–9 % shrink, and expect an alpha-case reaction layer that must be chemically removed.
What surface finishes work on Zr 702C?
Remove the mould reaction layer by grit blast plus HNO3–HF pickling, then passivate in nitric acid; optional anodic colouring, but do not electroplate or paint over unpickled alpha case.
Zr 702C 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 |
|---|---|---|
| Hfhafnium counted within Zr+Hf; non-nuclear grade | ≤ 4.5 | 2 |
| Fe+Cr | ≤ 0.2 | 0.1 |
| C | ≤ 0.05 | 0.02 |
| Ooxygen governs strength level | ≤ 0.16 | 0.11 |
| N | ≤ 0.03 | 0.01 |
| Hhydrogen limit critical to avoid hydride embrittlement | ≤ 0.01 | 0 |
| Zr+Hfcombined zirconium plus hafnium, minimum per ASTM B752 Gr 702C | ≥ 99.2 (balance) | — |
Zr 702C-SR — frequently asked
What is Zr 702C-SR used for?
Zr 702C-SR is typically used for cast pump casings, valve bodies and corrosive-service fittings. In short: cast version of Zr 702; top-tier acid corrosion resistance; most ductile cast Zr grade.
What is the yield strength of Zr 702C-SR?
Zr 702C-SR has a typical yield strength of 245 MPa (35.5 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 72% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.
Is Zr 702C-SR easy to machine?
Not especially — machinability is rated fair (36/100, better than 90% of refractory metal grades). Machine like austenitic stainless at low speed with heavy positive-rake sharp carbide tooling, rigid setup and flood coolant; chips and fines are pyrophoric — collect wet and never dry-grind.
Can Zr 702C-SR be welded?
Yes — weldability is rated very good (76/100). GTAW/plasma with high-purity argon or chamber welding and full backside/trailing shielding; keep O, N, H pickup low (weld must stay silver — straw or blue tint means rejectable contamination), no flux processes.
What surface finishes work on Zr 702C-SR?
Remove the mould reaction layer by grit blast plus HNO3–HF pickling, then passivate in nitric acid; optional anodic colouring, but do not electroplate or paint over unpickled alpha case.
Can Zr 702C-SR be formed, bent or molded?
Cast by vacuum/consumable-electrode skull melting into rammed graphite or investment moulds; allow generous risering and ~7–9 % shrink, and expect an alpha-case reaction layer that must be chemically removed.
What is the maximum service temperature of Zr 702C-SR?
Zr 702C-SR is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Zr 702C-F and Zr 702C-A?
F is the default condition — standard supply condition for corrosion-service pump and valve castings; meets B752 mechanical minima without further heat treatment. A: choose for maximum ductility and the most uniform, fully passive surface before service in aggressive acid duty. Yield strength is 250 MPa in F versus 230 MPa in A.
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 (Gr 702 property baseline) — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Zirconium) — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Zirconium) — ASM International (2005)
- Zirconium alloys 702/705 technical data — 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.