Precision Bellows and Assemblies

United Flexible provides precision engineered metal bellows, bellows assemblies, seamless tubes and thermal actuators. With over 100 years of experience in the engineering and manufacturing of metal bellows, we have developed a vast knowledge of applications and designs. Our design engineers are able to produce a bellows solution for the most basic applications, to those that are extremely complicated and unique. We are able to provide you these solutions supported by life test data and years of excellent field performance. The metal bellows solutions are used in many technology sectors such as to regulate pressure and temperature in aerospace and automobile applications, heating systems, medical equipment, gas turbines, oil & gas exploration, seals for industrial valves and electrical equipment.

Precision Metal Bellows

  • Capabilities: Outside Diameter Sizes between 0.250” (6.4 mm) to 12” (305 mm); multi-ply tubes 2-4 plies; temperature ranges from Cryogenic to 2000°F (1,093°C); pressure ranges from full vacuum to 3,000 psi (204 bar)
  • Materials: Stainless Steels 304, 321, 316L, 316Ti, 347
    • Inconel 625, Incoloy 600/718/800/825, Monel 400
    • Hastelloys C-22/C-276
    • Yellow Metals – Beryllium Cooper, Brass, Phosphor Bronze, Oxygen-free Copper
  • Applications: Aerospace/Defense, Critical Service Valves, Electrical Switchgear, Gas Turbines, Measurement & Control, Medical, Oil & Gas, Transportation

Bellow Assemblies

  • Joining Capabilities: Laser Welding, TIG Welding, Standard Brazing, Vacuum Brazing and Soldering
  • Quality Procedures: ISO9001:2008 registered quality system, Pressure Tests, Helium Leak tests to 1x 10-9 atm, Liquid & Dye Penetrant Testing, Life Cycle Testing, Proof Pressure Testing

Thermal Actuators

Act as non-electric motors that produce linear motion upon temperature changes

  • Capabilities: 40°F (4°C) to 300°F (150°C) activation temperatures. Movements of 0.020” (0.50 mm) to 0.370” (9.4 mm)
  • Materials: Various Wax Blends to meet your temperature and motion ranges
  • Applications: Thermostats, Ported Vacuum Switches, Thermal Flow Valves, Fuel Temperature Control, Safety Shutoff Devices

Quality ISO9001:2008 Materials

Fulton Bellows, LLC uses a wide assortment of metal to produce bellows. These materials include various grades of:

  • Stainless Steel
  • Inconel
  • Monel
  • Hastelloy
  • Copper
  • Phosphorus Bronze
  • Beryllium Copper
  • Brass

Our Design Engineers will work closely with you to select the material which is most appropriate to your application and requirements. Due to our coil slitting capability and our relationships with many metal sources, we stock many of these materials in master coils enabling rapid order launching.


After inventing thin wall metal bellows, then manufacturing metal bellows and metal bellows assemblies, Fulton Bellows has a lot of flexibility in tooling options to make every effort to keep costs to a minimum. This includes tooling specifically designed and machined for hydroforming and tube manufacturing. The depth of our tooling portfolio means we can reduce the time from design to prototypes to production.


Fulton Bellows is vertically integrated allowing greater flexibility in the manufacturing of bellows and bellows assemblies. From our master coils, we have the flexibility for custom seamless tube sizes. Our in house machine shop allows us to develop and maintain all of our tooling. We have various annealing and heat treating capabilities that permit us to process many different types of materials. Fulton Bellows has the capability to form bellows by hydroforming or mechanically forming depending on the application. Finally, our processes allow us to form many different end and bottom configurations. Key processes include:

  • Tube manufacturing
  • Seamless >= .0004 (0.10mm) material thickness and diameters from 0.170″ to 3.00″ (4.3 – 76.2mm)
  • Welded up to 12″ (304.8mm) in diameter
  • Annealing
  • Age Hardening
  • Hydroforming—0.250″ (6.4mm) to 4.500″ (114.3mm) in diameter
  • Mechanical roll forming

Welding / Joining / Valve Added

We have an on-staff welding engineer combined with other staff and technicians that provide years of welding experience using a wide variety of welding processes. This allows us to offer a wide range of opportunities to provide value added processing to your bellows. Processes include:

  • GTAW
  • Semi-automated GTAW
  • Resistance
  • Laser
  • Brazing and soldering
  • Induction brazing
  • Epoxy


Utilizing both in process and end of line testing, Fulton Bellows ensures that your product meets your specifications. Our testing regimen includes:

  • Inline process control using Zontec SPC software
  • Brinell Hardness Test
  • Cycle Testing
  • Pressure leak test
  • Mass Spectrometer (under vacuum 1×10-9 atm)
  • Dye Penetrant
  • Bubble jar
  • Spring rate
  • Other functional testing as required
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