Metal Bellows
Manufactured and custom metal expansion joints made to order from DN12 to DN2500.
24hr Shipping
On all stock items ordered.
Mon-Thur by 12:30pm, 9:30am Fridays
Design & Manufacturing
Full in-house design & manufacture to EN / ASME / PED.
ISO14001 Accreditation
FlexEJ has an accredited Environmental Management System.
Metal Expansion Bellows
FlexEJ offers a range of standard metal expansion joints as well as a full UK in-house manufacturing capability – typically to EJMA/B31.3/PED. Diameters from 25mm to 2500mm, design to specification.
PRODUCT GUIDES
METAL BELLOWS
WHAT IS A METAL EXPANSION BELLOW?
OFF THE SHELF TO FULL DESIGN AND MANUFACTURE…
Design
Extensive range of stock/configurable metal bellows and fully engineered expansion solutions.
Performance
High quality EJMA calculated bellows manufactured by punch forming in stainless steels, Nickel alloys, Exotics.
Application
FlexEJ are here to help from concept through to project delivery .
Projects
Full documentation, certification, NDT and engineering support.
How to specify a metal expansion joint
We design and manufacture metal expansion joints so you are not restricted to our range of standard products, some of which are available in our web shop. For simpler applications a standard product may be entirely suitable but if not we will design to meet your exact requirements.
Metal bellows have a defined fatigue life based on movement cycles. Understanding the movements, if they are concurrent or not and the realistic number of times the movements can occur is fundamental to metal bellows design.
Metal bellows work well up to around 500ºC, above that we use insulation to control the actual bellows metal temperature if the media is above this temperature. Pressure and temperature must be known to select a metal expansion joint.
The most common material used for metal bellows is Stainless Steel – 304, 321, 316 – and for more demanding applications Nickel Alloys – 625, 800, 825. Corrosion is the most likely failure mode for the bellows itself so the correct material selection is important.
Our standard ranges have set lengths for each diameter / movement range but we can design to meet your exact requirements. Making the bellows longer will increase the available movement. Most commonly a flange, we can provide to any specification, or pipe weld ends. Our HVAC standard product is available with BSP Union ends and Copper Pipe ends. If you are uncertain about what flange type you already have installed our Flange Finder will help you identify it.
Call our expert team on +44 (0) 1384 881188 or email us at sales@flexej.co.uk or use Live Chat on this web site – we are here to help, please get in touch.FlexEJ’s Metal Bellows Expansion Joints
FlexEJ has the following ranges available which cover all applications from simple HVAC up to refinery, power and nuclear:
INDUSTRIAL METAL BELLOWS
Fully Configurable
FlexEJ’s industrial metal bellows range is based around high performance bellows designed to EJMA and is fully configurable. You can then specify any flange type and material or weld end pipe type and material plus any end-to-end length within the design range. Rated up to 12 Barg @ 300 °C and backed by our engineering team.
PHARMACEUTICAL METAL BELLOWS
Aseptic Self Draining
FlexEJ’s pharmaceutical metal bellows design allows metal bellows to be deployed in lines that must be fully cleaned and aseptic. Self draining and manufactured from high surface finish stainless steel.
Metal bellows manufacturing
DN25 to DN2500+

MANUFACTURED METAL BELLOWS
Full design to EJMA/B31.3 or EN14917
FlexEJ design and manufacture fully engineered expansion joints. We work to all international codes and in materials to suit all applications including CrMO, Duplex 625, 800 and 825. Tied, hinged, gimbal, pressure balanced, refractory lined, liners, covers, single and multi ply and two ply testable bellows – we have the experience.
Metal Expansion Bellows Finders and Calculators
We have a couple of easy to use tools and calculators to help you locate the best metal expansion bellows from our next-day delivery stock items. Our Thermal Expansion Calculator for Piping helps you estimate the increase in length of a pipe run with temperature.
Our Advanced Bellows Finder is a quick way to navigate our stock range of bellows, both metal and rubber. With just a few choices you can arrive at the appropriate selection – criteria include pipe size, type, media compatibility, installation length, pressure rating, pipe connection type, conformance and movement axial, lateral and angular. All the products are in the online store with 24hr shipping as standard. If you’re not sure what flange you need our handy Flange Finder should also be useful.Stock Metal Bellows Finder
Do search for metal bellows by pipe size, intended media and/or connection hardware to see FlexEJ’s stock bellows options below but don’t hesitate to call us on 01384 881188 or email us for more bespoke or OEM options or if you need any advice at all.
Can't see what you want? Need help?
Call us. Or use Live Chat.
For instant advice. We can custom-design and engineer almost any expansion joint you need for delivery in the UK or worldwide. Call our expert team on +44 (0) 1384 881188 Or email us sales@flexej.co.uk
Frequently Asked Questions
A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.
A. Yes, FlexEJ has full design capability for engineered metal expansion joints and can work to any recognised standard – typically EJMA, B31.3/Appendix X, EN14917 plus PED and/or other customer specifications. Engineered rubber expansion joints are typically designed to meet the FSA guidelines plus PED and/or other customer specifications For technical assistance please contact us or use the Live Help link on this page.
A. Yes, if you have the details we can normally offer an equivalent, our FAQ here gives the information we will need for a full selection. For technical assistance please contact us or use the Live Chat link on this page.
A. To identify an existing expansion joint we need to know: nominal bore, overall length and flange type plus service, temperature, pressure and required movement if known. Try our Flange Finder to help identify the flange and you can send us a picture of the existing part using the Contact us form. For technical assistance please contact us or use the LIVE CHAT link on this page.
A. Yes, our MRCA copper ended metal expansion joints also have WRAS approval. We laso have DWI approval for stainless steel expansion joints. For technical assistance please contact us or use the Live Chat link on this page.







