Refractory Metal S-65C
ASTM B349 Grade S-65C
S-65C is the cross-rolled sheet form of S-65 beryllium, supplied to ASTM B349 Grade S-65C with more isotropic in-plane properties than unidirectionally rolled material.
Reference datasheet — S-65C 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 VHP condition
S-65C tempers and conditions
S-65C is supplied in 3 conditions, soft to hard. VHP 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 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 |
Supply forms, finishes and certifications
Ways S-65C is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
CR-Sheet | CR Sheet | Supply form |
ETCH | Machined + chemically etched surface | Surface finish |
What is S-65C?
S-65C is the cross-rolled sheet form of S-65 beryllium, supplied to ASTM B349 Grade S-65C with more isotropic in-plane properties than unidirectionally rolled material. It is specified for optical bench and mirror substrates and instrument structures, typically 241 MPa yield, 324 MPa tensile, 4.5% elongation, 90 HB and 210 W/m·K, in VHP, HIP, cold-rolled sheet, annealed and etched conditions. Cold formability is essentially nil, fusion welding is hot-crack prone and machining requires enclosed dust control; sheet gauges and lead times are limited. S-65 block is the choice for thicker machined parts. S-65C 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). S-65C has a yield strength of 241 MPa (35 ksi) and a tensile strength of 324 MPa (47 ksi) — weaker than 73% of refractory metal grades. Elongation at break is 4.5% and the elastic modulus is 303 GPa (43.9 Msi).
What is S-65C used for?
- optical mirror substrates
- aerospace instrument housings
- cryogenic optics
Advantages
- High electrical conductivity — 42 % IACS, better than 99% of refractory metal grades
- Lightweight — 1.85 g/cm³ (0.0668 lb/in³), better than 96% of refractory metal grades
- Conducts heat well — 210 W/m·K (121.3 BTU/hr·ft·°F), better than 94% of refractory metal grades
- Easy to machine — 40/100, better than 93% of refractory metal grades
Limitations
- Needs corrosion protection — 40/100, worse than 97% of refractory metal grades
- Difficult to weld — 15/100, worse than 93% of refractory metal grades
- Low fracture toughness — 11 MPa·√m (10 ksi·√in), worse than 92% of refractory metal grades
- Limited formability — 8/100, worse than 90% of refractory metal grades
- Limited ductility — 4.5%, worse than 81% of refractory metal grades
S-65C properties
Typical room-temperature values for S-65C-VHP; bars are the position among refractory metal grades.
Physical3
S-65C 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 has a yield strength of 241 MPa (35 ksi) and a tensile strength of 324 MPa (47 ksi) — weaker than 73% of refractory metal grades. Elongation at break is 4.5% and the elastic modulus is 303 GPa (43.9 Msi).
Thermal6
S-65C is rated for continuous service to 500°C (932 °F). It conducts heat at 210 W/m·K (121.3 BTU/hr·ft·°F), better than 94% of refractory metal grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
S-65C conducts electricity at 42 % IACS, better than 99% 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 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's machinability is fair (40/100, better than 93% of refractory metal grades); weldability poor (15/100); formability not recommended (8/100).
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. S-65C is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S-65C
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.
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) |
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.
Equivalent designations
Standards and trade names that resolve to Refractory Metal S-65C in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B349 Grade S-65C
How much does S-65C cost?
S-65C 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.
S-65C — frequently asked
What is S-65C used for?
S-65C 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?
S-65C has a typical yield strength of 241 MPa (35 ksi) and a tensile strength of 324 MPa (47 ksi) — weaker than 73% of refractory metal grades. Strength varies by condition: see the 3 listed tempers.
Is S-65C easy to machine?
Not especially — machinability is rated fair (40/100, better than 93% 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 be welded?
Not readily — weldability is rated poor (15/100). 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?
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 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?
S-65C 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.
How much does S-65C cost?
S-65C 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
- 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; 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.