KF / Vacuum Flanges
Stainless steel vacuum flanges — ISO-KF weld flanges KF16–KF50 and ISO-K weld, clamp and collar flanges 63–250 — sealed with an O-ring and centering ring and closed with a quick-release clamp.
Technical Data
| KF / Vacuum Flanges — specification | |
|---|---|
| ISO-KF | KF16–50 weld flange |
| ISO-K | ISO-K 63–250 clamp/collar |
| Material | SS 316/316L stainless |
| Seal | O-ring + clamp |
| ISO-KF range | KF16–KF50 weld flanges |
| ISO-K range | 63–250 weld / clamp / collar |
| Standards | DIN 28404 · ISO 1609 |
| Closure | Quick-release clamp |
| ISO-KF weld flanges | SS 316 / SS 304 |
| ISO-K 63 weld flange | SS 316L (machined) |
| ISO-K clamp / collar | AISI 304 · DIN 28404 + ISO 1609 |
| O-ring / seal | NBR · FKM (Viton) · centering ring |
Key points
- Vacuum pumps, chambers & manifolds
- Analytical & laboratory instruments
- Semiconductor & thin-film coating
- High-purity gas & process lines
- Flexible bellows-hose connections
Drawing & Dimensions
Flange OD, bore, tube diameter and length as listed below; the conical seat takes the O-ring and centring ring. Generic section, not to scale.
Click the drawing to enlarge
ISO-KF stainless SS 316 / 304 to ISO 2861 / DIN 28403; ISO-K collar/claw AISI 304 to DIN 28404 + ISO 1609. Flexible bellows hose NW16–NW50 to custom length on request.
Click the drawing to enlargeDatasheet & Documents
The official KF / Vacuum Flanges datasheet — specification, materials, standards and the complete dimension tables.
ISO 9001:2015 certified quality
How to Order
Worked example
KF25 · weld-nipple flange
SS 316 · Ø40 OD × 20 mm
FKM O-ring + centering ring
Wing-nut clampAlso in This Range
Questions & Answers
What is a KF vacuum flange?
A KF (Klein Flansch, also called NW or QF) flange is a quick-release vacuum connection: two symmetric flanges are pulled together over a centring ring and O-ring with a wing-nut clamp, needing no bolts. It suits rough and medium vacuum work and is made in stainless 316.
What is the difference between KF and NW flanges?
There is no difference — KF, NW and QF are alternative names for the same ISO quick-release small-flange standard. KF25 and NW25 describe the same connection.
What iso-kf do you supply for kf / vacuum flanges?
KF16–50 weld flange. Other sizes can usually be supplied on request — send your requirement for confirmation.
Which standards and grades are available?
ISO-KF weld flanges: SS 316 / SS 304 · ISO-K 63 weld flange: SS 316L (machined) · ISO-K clamp / collar: AISI 304 · DIN 28404 + ISO 1609. See the datasheet for the complete list.
What materials are offered?
SS 316 / 316L · AISI 304.
Is a technical datasheet available?
Yes — the official YTM Pipe datasheet with dimensions, materials and standards can be downloaded on this page.
How do I get a price?
Send size, specification and quantity through the Request-a-Quote form, WhatsApp or [email protected] — our team responds within one business day.
KF / Vacuum Flanges. Specified. Checked. Delivered.
Manufactured and supplied to the governing standard, inspected and documented before dispatch.