Refractory Metal S-200F-SR (Stress relieved)
Heat-treated state
ASTM B349 Grade S-200F
Specify for dimensionally critical optics and instrument parts after rough machining; maximises long-term stability at slightly lower strength.
Values for the SR condition
Other S-200F tempers and conditions
S-200F is listed in 3 conditions; see the grade overview at S-200F.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SRThis page Stress relieved | Specify for dimensionally critical optics and instrument parts after rough machining; maximises long-term stability at slightly lower strength. | 200 | 330 | 4 | 140 HB | 41 % IACS |
HPDefault Vacuum hot-pressed block | Standard stocked form: isotropic vacuum hot-pressed block for machined structures, mounts and instrument housings. | 262 | 370 | 3 | 150 HB | 40 % IACS |
Hot isostatic pressed | Pick when near-net shapes, larger sections or slightly higher strength/uniformity than hot-pressed block are needed. | 296 | 414 | 3.5 | 165 HB | 40 % IACS |
What is S-200F-SR?
S-200F-SR is S-200F heat treated to SR — specify for dimensionally critical optics and instrument parts after rough machining; maximises long-term stability at slightly lower strength. S-200F-SR has a yield strength of 200 MPa (29 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 87% of refractory metal grades. Elongation at break is 4% and the elastic modulus is 303 GPa (43.9 Msi). S-200F-SR 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). HP is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Conducts heat well — 218 W/m·K (126 BTU/hr·ft·°F), better than 101% of refractory metal grades
- Lightweight — 1.85 g/cm³ (0.0668 lb/in³), better than 96% of refractory metal grades
- High electrical conductivity — 41 % IACS, better than 96% of refractory metal grades
Limitations
- Hard to polish — 45/100, worse than 98% of refractory metal grades
- Low strength — 200 MPa (29 ksi), worse than 87% of refractory metal grades
- Low fracture toughness — 12 MPa·√m (10.9 ksi·√in), worse than 87% of refractory metal grades
- Needs corrosion protection — 45/100, worse than 86% of refractory metal grades
- Limited ductility — 4%, worse than 84% of refractory metal grades
S-200F-SR properties
Typical room-temperature values for S-200F-SR; 22 are specific to this condition. Other listed values are S-200F reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
S-200F-SR 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).
Mechanical16
S-200F-SR has a yield strength of 200 MPa (29 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 87% of refractory metal grades. Elongation at break is 4% and the elastic modulus is 303 GPa (43.9 Msi).
Thermal6
S-200F-SR is rated for continuous service to 500°C (932 °F). It conducts heat at 218 W/m·K (126 BTU/hr·ft·°F), better than 101% of refractory metal grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
S-200F-SR conducts electricity at 41 % IACS, better than 96% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 86% of refractory metal grades.
Sustainability4
Producing a kilogram of S-200F-SR takes about 1,400 MJ of energy and emits 90 kg of CO₂ — more than 67% of refractory metal grades. Typical recycled content is 15%.
Manufacturability7
S-200F-SR's machinability is fair (38/100, better than 90% of refractory metal grades); weldability poor (22/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S-200F-SR
Is S-200F easy to machine?
Machines like a hard, abrasive ceramic-metal: carbide/diamond tooling, light finishing passes, then chemical etch to remove the microcracked surface layer — all cutting must be wet or fully enclosed with HEPA extraction because Be dust is a chronic health hazard (OSHA/GB beryllium exposure limits apply).
Can S-200F be welded?
Poor fusion weldability — hot cracking and grain-boundary BeO; use electron-beam or GTAW with Al-Si (e.g. 718) filler, low heat input, and prefer mechanical fastening, adhesive bonding or Al-Si/Ag brazing.
Can S-200F be formed, bent or molded?
Essentially unformable at room temperature (≈3% elongation, basal-slip anisotropy); bend, draw or size only warm at 400–800 °C in dies, or design as a machined-from-block part.
What surface finishes work on S-200F?
No anodizing; typical finishes are chromate/chemical passivation, electroless nickel or ion-plated Al for handling and corrosion protection, plus acid etch for fatigue-critical surfaces.
S-200F 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 | ≤ 1.5 | 1 |
| Al | ≤ 0.1 | 0.06 |
| C | ≤ 0.15 | 0.07 |
| Fe | ≤ 0.13 | 0.09 |
| Mg | ≤ 0.08 | 0.02 |
| Si | ≤ 0.06 | 0.03 |
| other metallic impurities (each)per ASTM B349 limits | ≤ 0.04 | — |
| Beassay, minimum | ≥ 98.5 (balance) | — |
S-200F-SR — frequently asked
What is S-200F-SR used for?
S-200F-SR is typically used for spacecraft structural panels, gyroscopes, optical mirrors and missile guidance components. In short: most-used structural beryllium; very high specific stiffness; toxic dust, enclosed machining.
What is the yield strength of S-200F-SR?
S-200F-SR has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 87% of refractory metal grades. Strength varies by condition: see the 3 listed tempers.
Is S-200F-SR easy to machine?
Not especially — machinability is rated fair (38/100, better than 90% of refractory metal grades). Machines like a hard, abrasive ceramic-metal: carbide/diamond tooling, light finishing passes, then chemical etch to remove the microcracked surface layer — all cutting must be wet or fully enclosed with HEPA extraction because Be dust is a chronic health hazard (OSHA/GB beryllium exposure limits apply).
Can S-200F-SR be welded?
Not readily — weldability is rated poor (22/100). Poor fusion weldability — hot cracking and grain-boundary BeO; use electron-beam or GTAW with Al-Si (e.g. 718) filler, low heat input, and prefer mechanical fastening, adhesive bonding or Al-Si/Ag brazing.
What surface finishes work on S-200F-SR?
No anodizing; typical finishes are chromate/chemical passivation, electroless nickel or ion-plated Al for handling and corrosion protection, plus acid etch for fatigue-critical surfaces.
Can S-200F-SR be formed, bent or molded?
Essentially unformable at room temperature (≈3% elongation, basal-slip anisotropy); bend, draw or size only warm at 400–800 °C in dies, or design as a machined-from-block part.
What is the maximum service temperature of S-200F-SR?
S-200F-SR 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-200F-HP and S-200F-SR?
HP is the default condition — standard stocked form: isotropic vacuum hot-pressed block for machined structures, mounts and instrument housings. SR: specify for dimensionally critical optics and instrument parts after rough machining; maximises long-term stability at slightly lower strength. Yield strength is 262 MPa in HP versus 200 MPa in SR.
Sources
- ASTM B349/B349M — Beryllium Lump, Pebble and Hot-Pressed Block — ASTM International (2019)
- SAE AMS 7906 — Beryllium Hot-Pressed Block — SAE International (2018)
- S-200F Structural Grade Beryllium data sheet — Materion Beryllium & Composites (2021)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (Beryllium) — ASM International (1990)
- Beryllium Science and Technology, Vol. 1–2 — Plenum Press (1979)
- ASM Handbook Vol.13B — Corrosion: Materials (Beryllium) — ASM International (2005)
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.