KF (QF) and ISO Flanges
ANCORP’s KF (QF) and ISO (LF) flanges are available in a variety of designs and materials for easy integration into high vacuum systems and components. Available flange types include bored weld flanges, blank flanges, and unbored stub flanges. All KF and ISO flanges are manufactured to ISO specifications to ensure 100% compatibility with other vacuum flange manufacturers’ components. ANCORP offers KF and ISO flanges in 304 stainless steel, 316 stainless steel, and 6061 aluminum.
KF Flanges (ISO-QF Quick Flanges)
KF flanges, also called QF or NW flanges, are used to form high vacuum connections in 1/2″ (QF10) to 2″ (QF50) diameter vacuum system tubing. KF flanges are sexless, infinitely rotatable, and fastened with quick clamps that compress an elastomer O-Ring held in a centering ring between two flange faces to create a high vacuum seal.
ISO KF flange sizes reference the inner diameter in millimeters of vacuum tubing. A KF flange size chart can be found below.
KF Flange Size Chart
| ISO Size | Tubing I.D. (mm) | Flange Reference | Tubing O.D. (in.) |
|---|---|---|---|
| NW10 | 10 | QF10 | 0.50 |
| NW16 | 16 | QF16 | 0.75 |
| NW25 | 25 | QF25 | 1.00 |
| NW40 | 40 | QF40 | 1.50 |
| NW50 | 50 | QF50 | 2.00 |
ISO Flanges (ISO-LF Large Flange)
ISO flanges are used to form high vacuum connections in 2.5″ (LF63) to 20″ (LF500) diameter vacuum system tubing. ISO flanges are sexless, infinitely rotatable, and fastened with claw clamps or bolts to compress an elastomer O-Ring held in a centering ring between two flange faces to create a high vacuum seal. Two types of ISO flanges with different fastening styles exist. ISO LF flanges, also called ISO-K flanges, use claw clamps secured to an outer rim on the flanges to fasten.
ISO flange sizes reference the inner diameter in millimeters of vacuum tubing. An ISO flange size chart can be found below.
ISO Flange Size Chart
| ISO Size | Tubing I.D. (mm) | Flange Size | Tubing O.D. (in.) |
|---|---|---|---|
| NW63 | 63 | LF63 | 2.50 |
| NW80 | 80 | LF80 | 3.00 |
| NW100 | 100 | LF100 | 4.00 |
| NW160 | 160 | LF160 | 6.00 |
| NW200 | 200 | LF200 | 8.00 |
| NW250 | 250 | LF250 | 10.00 |
| NW320 | 320 | LF320-1200 | 12.00 |
| NW320 | 320 | LF320-1275 | 12.75 |
| NW400 | 400 | LF400 | 16.00 |
| NW500 | 500 | LF500 | 20.00 |
KF and ISO Flange Types
Blank flanges are manufactured with no weld prep and no tubing bore. They are commonly used to close unused ports or they are altered by customers with their own machining capability for special use. ANCORP offers QF blank flanges and LF blank flanges.
Weld flanges are manufactured with a weld prep and tubing bore for immediate installation on your vacuum system with no additional alteration. We offer weld flanges in four different designs to meet your specific requirements:
- QF Bored Weld Flanges – have a standard weld prep. QF bored weld flanges
- Socket Weld Flanges – designed with a tube counterbore for internal welds. QF socket weld flanges and LF Socket weld flanges.
- QF Weld Ring Flanges – similar to socket weld flanges but have a thinner cross-sectional profile
- Stub Weld Flanges – designed for butt welds. QF stub weld flanges are available.
QF Unbored stub flanges are manufactured with no weld prep and no tubing bore. They are commonly altered by customers with their own custom machining capability for special use.