Introduction
DN50CF (3.375″ OD) 304L Stainless Steel Standard ConFlat® (CF) UHV Flanges are industry-standard vacuum interfaces engineered for ultra-high-vacuum applications that demand repeatable, metal-sealed performance. Their compact size and proven knife-edge sealing make DN50CF flanges a common choice for pumps, valves, viewports, and instrumentation ports in semiconductor, coating, and research systems.
Detailed Description
DN50CF flanges are precision-machined from vacuum-grade 304L stainless steel, selected for its low carbon content, excellent corrosion resistance, and low outgassing characteristics. The accurately formed CF knife edges create a reliable metal-to-metal seal when compressed against an OFHC copper gasket, supporting true UHV performance and repeated bakeout cycles.
With a 3.375 inch (85.7 mm) outer diameter, DN50CF flanges conform fully to international ConFlat® standards, ensuring seamless interchangeability with compatible elbows, tees, reducers, valves, and feedthroughs. The robust construction maintains dimensional stability during thermal cycling, helping preserve seal integrity over long service life.
Applications
UHV pumping lines and isolation valves
Thin film deposition systems (PVD, sputtering, evaporation)
Semiconductor process equipment and load-locks
Analytical and surface science instruments
Research and industrial UHV vacuum manifolds
Technical Parameters
| Parameter | Typical Value / Range | Importance |
|---|---|---|
| Flange Type | ConFlat® (CF), DN50 | Standard UHV interface |
| Outer Diameter | 3.375″ (85.7 mm) | Compact, widely compatible |
| Material | 304L Stainless Steel | Low outgassing, corrosion resistance |
| Sealing Method | Knife-edge with copper gasket | Proven UHV metal seal |
| Bolt Pattern | DN50CF standard | Interchangeable CF hardware |
| Bakeout Temperature | Up to ~450 °C | Suitable for UHV processes |
| Leak Rate | ≤ 1×10⁻¹⁰ mbar·L/s (typical) | Maintains UHV integrity |
Comparison with Related CF Flanges
| Flange Size | Key Advantage | Typical Application |
|---|---|---|
| DN50CF (304L SS) | Balanced size & conductance | Valves, pumps, diagnostics |
| DN25CF | Smaller footprint | Gauges & feedthroughs |
| DN63CF | Higher conductance | Main pumping connections |
FAQ
| Question | Answer |
|---|---|
| Are copper gaskets included? | Typically supplied separately unless requested. |
| Is 304L suitable for repeated bakeouts? | Yes, 304L supports repeated UHV bake cycles. |
| Are electropolished versions available? | Yes, electropolishing can be provided on request. |
| Can custom drilling or thickness be supplied? | Standard patterns are typical; custom options can be discussed. |
| How are knife edges protected in transit? | Protective caps are used to prevent damage. |
Packaging
Our DN50CF 304L SS Standard ConFlat® UHV Flanges are cleaned for vacuum service, with knife edges protected by caps. Each flange is individually packed using protective materials and shipped in export-grade cartons or wooden crates to ensure safe delivery.
Conclusion
DN50CF (3.375″ OD) 304L SS Standard ConFlat® (CF) UHV Flanges deliver dependable metal sealing, excellent thermal stability, and full compatibility with global CF standards. Their precision machining and robust materials make them a reliable solution for UHV systems in semiconductor manufacturing, research laboratories, and advanced vacuum applications.
For detailed specifications and a quotation, please contact us at sales@thinfilmmaterials.com.
Through (Clearance) Holes
Are through-holes that allow adequate clearance for bolts to go through both flanges and secured by nuts or plate nuts.
Tapped Holes
Are imperial or metric threaded holes machined through the flange. This allows a clearance-hole flange to be connected without the need for nuts or plate nuts. Be aware of a components bolt hole orientation when selecting tapped flanges.
Ordering Table
| Flange Size/OD | Type | Flange Material | Drawing | Nominal Tube OD | Bore | Counter Bore | Thickness | Bolt Circle Dia. | Bolt Hole Dia. | # of Bolt Holes | Thread Size | Setback | Part Number |
| DN50CF (3.38" OD) | Fixed Tapped | 304L SS |
| — | Blank | — | 0.63 | 2.850 | — | 8 | M8 x 1.25P | — | F0337X000M |
| DN50CF (3.38" OD) | Fixed | 304L SS |
| — | Blank | — | 0.63 | 2.850 | 0.33 | 8 | — | — | F0337X000N |
| DN50CF (3.38" OD) | Fixed Tapped | 304L SS |
| — | Blank | — | 0.63 | 2.850 | — | 8 | 5/16-24 | — | F0337X000NT |
| DN50CF (3.38" OD) | Rotatable | 304L SS |
| — | Blank | — | 0.68 | 2.850 | 0.33 | 8 | — | — | F0337X000R |
| DN50CF (3.38" OD) | Rotatable Tapped | 304L SS |
| — | Blank | — | 0.68 | 2.850 | — | 8 | 5/16-24 | — | F0337X000RT |
| DN50CF (3.38" OD) | Fixed | 304L SS |
| 1-1/2 | 1.44 | 1.510 | 0.63 | 2.850 | 0.33 | 8 | — | 0.225 | F0337X150N |
| DN50CF (3.38" OD) | Fixed Tapped | 304L SS |
| 1-1/2 | 1.44 | 1.510 | 0.63 | 2.850 | — | 8 | 5/16-24 | 0.225 | F0337X150NT |
| DN50CF (3.38" OD) | Rotatable | 304L SS |
| 1-1/2 | 1.44 | 1.520 | 0.68 | 2.850 | 0.33 | 8 | — | 0.225 | F0337X150R |
| DN50CF (3.38" OD) | Rotatable Tapped | 304L SS |
| 1-1/2 | 1.44 | 1.520 | 0.68 | 2.850 | — | 8 | 5/16-24 | 0.225 | F0337X150RT |
| DN50CF (3.38" OD) | Fixed | 304L SS |
| 2 | 1.94 | 2.010 | 0.63 | 2.850 | 0.33 | 8 | — | 0.225 | F0337X200N |
| DN50CF (3.38" OD) | Fixed Tapped | 304L SS |
| 2 | 1.94 | 2.010 | 0.63 | 2.850 | — | 8 | M8 x 1.25P | 0.225 | F0337X200NM |
| DN50CF (3.38" OD) | Fixed Tapped | 304L SS |
| 2 | 1.94 | 2.010 | 0.63 | 2.850 | — | 8 | 5/16-24 | 0.225 | F0337X200NT |
| DN50CF (3.38" OD) | Rotatable | 304L SS |
| 2 | 1.94 | 2.020 | 0.68 | 2.850 | 0.33 | 8 | — | 0.225 | F0337X200R |
| DN50CF (3.38" OD) | Rotatable Tapped | 304L SS |
| 2 | 1.94 | 2.020 | 0.68 | 2.850 | — | 8 | 5/16-24 | 0.225 | F0337X200RT |
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