Since 1978, GAMI CRYO & MECA has been designing bimetallic transition joints of aluminum / stainless steel, known across the world as “T+C Transition Joints”.

We now have more than 40 years’ experience in the product and the manufacturing process, confirming the Gami Group’s position as leader on the bimetallic transition joint market.

Manufacturing of bimetallic transition joints

The technology behind the transition joint derives from many years of co-development between CEA and T&C

The “transition joint” is the result of a co-development by the CEA

(Commissariat à l’Energie Atomique) and T&C (Thévenet et Clerjounie) which subsequently became


Production processes

This technology was designed as a way of overcoming the issue of connecting a part comprising two heterogeneous metal grades under pressure. A bimetallic transition joint is a safety part connecting aluminum parts to stainless steel parts. More accurately, the heart of the application is based on an ASU (Air Separation Unit) forming a link between aluminum heat exchangers and stainless steel processing columns. Our connections are absolutely air tight and can resist a pressure exceeding that of the assembly in which they are installed.

Hot stamping

Bimetallic aluminum/stainless steel sintering under temperature control

Thermal expansion /
weld-free interface

Increased resistance to pressure in the connections under the effects of heat.

Hydrostatic testing up
to 400 bar

Hydraulic pressurizing to guarantee resistance to high pressure.

Mechanical design

High-strength mechanical design tolerating many constraints (twisting/shearing/pulling).

Diffusion interface

Bimetallic aluminum/stainless steel sintering under temperature control

Helium testing to
10-9 mbar.l.s-1

Testing at internal negative pressure with helium atmosphere to guarantee maximum air-tight seal.

Full traceability from casting
through to finished part

Electrochemical marking with temperature gauge offering full traceability.


We can supply you with connections from dia. 8 mm to dia. 1200 mm, made to suit your design and your overall dimensions. We can also develop a design specific to your application.

Product qualifications

The Gami Group is your expert in bimetallic transition joints. For more than 40 years, we have been assisting our customers and meeting their demands. We operate on all the different continents, in small or mega-sized factories. Gami has all the skills needed to manufacture connections adapted to your specification and capable of resisting the toughest conditions. We have every certification that your application might require. We accompany our customers with the R&D of their future installations.

ASME VIII div.1 certification

DESP 2014/68/UE

Design examination

Thermal shock test

Hydrostatic shattering test

Periodic inspection

Annual quality audit

The Gami Group operates in many
different activity sectors

We are there to listen to what you need and adjust to every particular environment.

Cryogenics / LNG


Oil & Gas




Maritime industry


Renowned world expert in cryogenics and pressure equipment

Contact information

These bimetallic transition joints are produced in our GAMI CRYO & MECA facility in the Auvergne-Rhône-Alpes region of FRANCE.

Contact +33 4 72 02 68 00

Our expertise in motion