Rotatable or nonrotatable with tapped or clearance bolt holes
Flange: 304 stainless steel (316L available on request)Gaskets: Viton, copper or silver platedBolts: 18-8 stainless steel or silver plated
Metal seal: >1 x 10-13 mbar - UHVElastomer seal: >1 x 10-8 mbar - High vacuum
Metal seal: -200ºC to 450ºCElastomer seal: -20ºC to 150ºC
Nominal OD sizes:
11/3 to 161/2 inches (34-419mm)
All dimensions are in inches (mm) & weights are in pounds (kg), unless otherwise noted.
CF Flanges and Fittings
Nor-Cal CF flanges are compatible with other Conflat style flanges and are available in sizes from 11/3 to 161/2 inch (33.96-419.1) OD for 1/4 to 14 inch (6.35-355.6) tube diameters. Normally our standard material is in the low carbon range for 304. Flanges are made from 304 that has been specially treated to remove impurities inherent in 300 series steels. Special UHV-flanges 4 1⁄2 (114.3) inches OD and smaller can be made from 304 electroslag remelt (ESR) bar stock. ESR is a refining pro- cess that produces stainless steel with higher purity, fewer inclusions and more uniform grain structure to eliminate microscopic leak paths. Our standard flange material is certified to meet ASTM A-240 and has less than 0.01% sulfur to prevent sulfur stringers. Grain size is 3 to 6 per ASTM E-112. Maximum inclusion size is 2.5 per ASTM E-45. As specials, 304L and 316L material can be supplied in roll-forged rings. Machining is consistent with good UHV practice. Machine coolant is sulfur free to reduce outgassing. State-of-the-art CNC machine centers are used to produce flanges with consistent high quality. Flanges are machine washed in approved aqueous detergent after machining. Chem-cleaning and clean room packaging are available.
CF flanges utilize an OFHC copper gasket to produce a vacuum tight seal up to 10-13 mbar, even when baked repeatedly to 450oC. When the copper gasket is compressed between the knife edges of CF flanges, its material flows laterally to fill surface imperfections.
Nor-Cal offers CF flanges in rotatable as well as nonrotatable versions. When components of several systems are used interchangeably, the use of rotatable flanges is recommended. Assembly is facilitated by rotating the receiver portion of the flange to align its bolt holes with those of the mating flange. The insert is welded to the tube or component and contains the knife edge portion of the CF flange.
Nonrotatable CF flanges, unlike rotatable, contain both sealing surface and bolt holes in one unit. This makes the nonrotatable flange less expensive, and therefore the preferred choice when mating component orientation is not a concern. All fittings are priced with a rotatable flange opposing a non rotatable. For fittings with all nonrotatable flanges subtract the difference in price between a rotatable and nonrotatable flange of the desired size multiplied by the number of additional nonrotatable flanges.
Metric Flanges and Hardware
Nor-Cal now stocks bored metric tapped CF flanges in 23/4, 41/2, 6, 8 and 10 inch (69.85, 114.3, 152.5, 203.2 and 254mm) ODs. Other sizes are available upon request. Fasteners for metric flanges are stocked for each flange size.
Silver plated Gaskets and Bolts
We are now offering silver plated copper gaskets and bolt kits in a variety of sizes. Silver plated copper gaskets are recommended when the use of pure copper is unacceptable. Silver plated bolt kits offer an alternative to using anti-seize thread lubricant.