UN Type
expansion joints

UN Type <br/>expansion joints For a larger view, please mouseover the image.
For a larger view, please mouseover the image.
Item Description
1 Flange
2 Bellows
3 Tie rod
4 Internal liner
5 Lug
6 Center spool
  • (Tied) custom metal expansion joints for general pressure applications.
  • Designed to cover the mid temperature and pressure range for general process equipment.
  • Suited for combined and multiple types of movements.
  • Tied metal expansion joints retain pressure thrust developed by internal pressure, through the use of hardware.
  • Multiply bellows with low spring rate and high cycle life.
  • Covers many applications
  • UN Types does not require anchor points being designed for obtaining pressure thrust, due to the installed hardware.
  • Highly customizable design: Bellows geometry, Material options and combinations.
Diameter: DN 40 ... DN 5,000 (1.5" ... 100”)
Temperature: ... 700 °C (1,292 °F)
Pressure: max. 50 barg (725 PSIG)
  • Bellows: 1.4541 (AISI 321); 1.4301 (AISI 304); 1.4306 (AISI 304L); 1.4401 (AISI 316); 1.4404 (AISI 316L); 1.4571 (AISI 316Ti); 1.4828 (AISI 309); 1.4547 (254 SMO); 2.4816 (Inconel® 600); 2.4856 (Inconel® 625/LCF); 1.4876 (Incoloy® 800/H)
  • Connections: 1.0038 – (S235JRG2); 1.0460 – (P250GH); 1.0315 – ; 1.0254 (P235TR1); 1.0425 – (P265GH); 1.5415 – (16Mo3); 1.7335 – (13CrMo4-5); 1.4401 (AISI 316); 1.4404 (AISI 316L);1.4541 (AISI 321)
  • Flanges: 1.0038 - S235JRG2; 1.0425 - P265GH; 1.0315 - P235G2TH; 1.0254 (P235TR1); 1.0425 - P265GH; 1.5415 - 16Mo3; 1.7335 – 13CrMo4-5;1.4404 (AISI 316L); 1.4436 (AISI 316)


Other materials are available on request.
Design code:
EJMA 9, PED 97/23/EC according to: EN 13480, EN 13445, EN 14917, AD2000 and ASME B31.3


NDT and documentation:
According to PED 97/23 EC rules and regulations (declaration of conformity).
Documentation can be provided per customer request e.g.:
- Test, measurement or calculation reports
- Material test or inspection certificates
- Design, type or 3rd party approval
  • Refining technology
  • Oil and gas industry
  • Power plant technology
  • Pulp and paper industry
  • Shipbuilding
  • Water and waste water technology
  • Gas and steam turbines
  • Conventional boilers
  • Coal feed transport systems
  • Ash transport systems
  • Water cooling systems
  • Air and steam transport lines
  • Compressor / pumping stations
  • Lubrication systems
  • Storage tanks
Tied metal expansion joints might require alignment guides to ensure the expansion joint only see the intended movements.