Refractory Metal S-65C-ANN (Annealed)
Heat-treated state
ASTM B349 Grade S-65C
Use after heavy machining or forming to remove residual stress and twinned damage for maximum dimensional stability in metrology parts.
Values for the ANN condition
Other S-65C tempers and conditions
S-65C is listed in 3 conditions; see the grade overview at S-65C.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page Annealed | Use after heavy machining or forming to remove residual stress and twinned damage for maximum dimensional stability in metrology parts. | 225 | 310 | 5.5 | 85 HB | 43 % IACS |
VHPDefault Vacuum hot pressed block | Standard supply form for S-65C: near-isotropic fine-grain block for optical benches, mirror substrates and structural fittings. | 241 | 324 | 4.5 | 90 HB | 42 % IACS |
Hot isostatic pressed | Choose when full density, minimal porosity and the most isotropic properties in thick sections are required (near-net shapes, cryogenic optics). | 255 | 345 | 5 | 95 HB | 43 % IACS |
What is S-65C-ANN?
S-65C-ANN is S-65C heat treated to ANN — use after heavy machining or forming to remove residual stress and twinned damage for maximum dimensional stability in metrology parts. S-65C-ANN has a yield strength of 225 MPa (32.6 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 79% of refractory metal grades. Elongation at break is 5.5% and the elastic modulus is 303 GPa (43.9 Msi). S-65C-ANN has a density of 1.85 g/cm³ (0.0668 lb/in³), lighter than 96% of refractory metal grades. It melts at 1,287°C (2,349 °F). VHP is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- High electrical conductivity — 43 % IACS, better than 101% of refractory metal grades
- Conducts heat well — 215 W/m·K (124.2 BTU/hr·ft·°F), better than 99% of refractory metal grades
- Easy to machine — 45/100, better than 99% of refractory metal grades
- Lightweight — 1.85 g/cm³ (0.0668 lb/in³), better than 96% of refractory metal grades
Limitations
- Needs corrosion protection — 40/100, worse than 97% of refractory metal grades
- Difficult to weld — 18/100, worse than 90% of refractory metal grades
- Low fracture toughness — 11.5 MPa·√m (10.5 ksi·√in), worse than 88% of refractory metal grades
- Limited formability — 12/100, worse than 84% of refractory metal grades
- Low strength — 225 MPa (32.6 ksi), worse than 79% of refractory metal grades
S-65C-ANN properties
Typical room-temperature values for S-65C-ANN; 22 are specific to this condition. Other listed values are S-65C reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
S-65C-ANN has a density of 1.85 g/cm³ (0.0668 lb/in³), lighter than 96% of refractory metal grades. It melts at 1,287°C (2,349 °F).
Mechanical15
S-65C-ANN has a yield strength of 225 MPa (32.6 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 79% of refractory metal grades. Elongation at break is 5.5% and the elastic modulus is 303 GPa (43.9 Msi).
Thermal6
S-65C-ANN is rated for continuous service to 500°C (932 °F). It conducts heat at 215 W/m·K (124.2 BTU/hr·ft·°F), better than 99% of refractory metal grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
S-65C-ANN conducts electricity at 43 % IACS, better than 101% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 97% of refractory metal grades.
Sustainability3
Producing a kilogram of S-65C-ANN takes about 1,500 MJ of energy and emits 95 kg of CO₂ — more than 77% of refractory metal grades. Typical recycled content is 15%.
Manufacturability7
S-65C-ANN's machinability is fair (45/100, better than 99% of refractory metal grades); weldability poor (18/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S-65C-ANN
Is S-65C easy to machine?
Machines like a brittle low-ductility metal — sharp carbide/diamond tools, light finishing cuts, flood coolant and fully enclosed HEPA-filtered dust control are mandatory (beryllium sensitisation/CBD hazard); follow with chemical etch to remove the twinned damage layer.
Can S-65C be welded?
Very difficult: fusion welding is hot-crack prone, so use electron-beam or GTAW with Al-Be (AlBeMet-type) filler, or prefer brazing/diffusion bonding and mechanical fastening.
Can S-65C be formed, bent or molded?
Essentially no cold formability; sheet is warm formed at roughly 400–800 °C with slow strain rates, and the grade is normally machined from VHP/HIP stock instead of formed.
What surface finishes work on S-65C?
Chromate conversion, proprietary anodize or electroless nickel is applied for corrosion protection; optical surfaces are typically nickel-clad then diamond-turned/polished, and all wet finishing must capture Be-bearing effluent.
S-65C 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 |
|---|---|---|
| BeOberyllium oxide dispersoid | ≤ 1 | 0.7 |
| C | ≤ 0.1 | 0.05 |
| Fe | ≤ 0.08 | 0.05 |
| Al | ≤ 0.06 | 0.03 |
| Mg | ≤ 0.06 | 0.02 |
| Si | ≤ 0.06 | 0.02 |
| Other metallic impurities (each) | ≤ 0.04 | — |
| Beassay, beryllium content | ≥ 99 (balance) | — |
S-65C-ANN — frequently asked
What is S-65C-ANN used for?
S-65C-ANN is typically used for optical mirror substrates, aerospace instrument housings and cryogenic optics. In short: cross-rolled isotropic Be sheet; optical substrate grade; sheet form of S-65.
What is the yield strength of S-65C-ANN?
S-65C-ANN has a typical yield strength of 225 MPa (32.6 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 79% of refractory metal grades. Strength varies by condition: see the 3 listed tempers.
Is S-65C-ANN easy to machine?
Reasonably — machinability is rated fair (45/100, better than 99% of refractory metal grades). Machines like a brittle low-ductility metal — sharp carbide/diamond tools, light finishing cuts, flood coolant and fully enclosed HEPA-filtered dust control are mandatory (beryllium sensitisation/CBD hazard); follow with chemical etch to remove the twinned damage layer.
Can S-65C-ANN be welded?
Not readily — weldability is rated poor (18/100). Very difficult: fusion welding is hot-crack prone, so use electron-beam or GTAW with Al-Be (AlBeMet-type) filler, or prefer brazing/diffusion bonding and mechanical fastening.
What surface finishes work on S-65C-ANN?
Chromate conversion, proprietary anodize or electroless nickel is applied for corrosion protection; optical surfaces are typically nickel-clad then diamond-turned/polished, and all wet finishing must capture Be-bearing effluent.
Can S-65C-ANN be formed, bent or molded?
Essentially no cold formability; sheet is warm formed at roughly 400–800 °C with slow strain rates, and the grade is normally machined from VHP/HIP stock instead of formed.
What is the maximum service temperature of S-65C-ANN?
S-65C-ANN is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S-65C-VHP and S-65C-ANN?
VHP is the default condition — standard supply form for S-65C: near-isotropic fine-grain block for optical benches, mirror substrates and structural fittings. ANN: use after heavy machining or forming to remove residual stress and twinned damage for maximum dimensional stability in metrology parts. Yield strength is 241 MPa in VHP versus 225 MPa in ANN.
Sources
- S-65C Structural Grade Beryllium — property data — Materion Beryllium & Composites (2021)
- ASTM B349/B349M — Specification for Beryllium Ingot and Hot-Pressed Block — ASTM International (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Beryllium) — ASM International (1990)
- Beryllium Science and Technology / Beryllium Chemistry and Processing — ASM International (2009)
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.