Cupal is a copper cladding on aluminum

The two metals are welded together in a special process.

CUPAL is a copper cladding on aluminum. In a special process, copper is welded together with aluminum in an inseparable manner. CUPAL is a composite material (group of non-ferrous metals) and not an alloy. The replacement material CUPAL has been tested for many years and in a variety of applications and has proven itself in place of pure copper and brass.


CUPAL is a cold-rolled composite material between aluminum and copper as a substrate material. 

Special properties of CUPAL

CUPAL combines the advantages of light metals – low specific weight (low dead weight), easy formability, etc. – with the advantages of copper such as corrosion resistance, solderability, galvanizability, special properties for electrical purposes.
The copper or aluminum sides of CUPAL behave in both chemical and physical terms like pure copper or pure aluminum. CUPAL enables corrosion-resistant connections between heavy and light metals.
CUPAL is characterized by good thermal conductivity. The electrical conductivity of CUPAL is favorable and reaches conductivity equality with pure copper at high-frequency currents. The contact values are even better than for pure copper.
CUPAL sheets can be processed on a cold way by drawing, pressing, stamping, rolling, bending, folding, riveting, etc., and can be soft-soldered and galvanized in a simple way like pure copper.

CUPAL - Productinformation

The composite material CUPAL is versatile

CUPAL is a cold-rolled composite material consisting of aluminum as the carrier material and copper as the overlay material. This composite material is used in the electrical industry as a contact or transition element between conductors made of aluminum and copper.

Manufacturing process of CUPAL

CUPAL can be further processed by cold forming due to the only microscopically thin alloy layer, e.g., bending, flanging, edging, stamping, profiling, stretching, and deep drawing. In the event of too strong an increase in strength as a result of cold forming, the original forming ability can be restored by heat treatment. However, the heat treatment should not exceed 260 degrees C/4 h.
  • The composite material CUPAL is manufactured by cold-rolled lamination.

  • After a surface treatment tailored to the respective material, aluminum and copper are firmly bonded together under high pressure in a lamination mill.

  • The material hardening caused by this must be removed by a suitable heat treatment to achieve the desired properties.

  • At the same time, the adhesion between aluminum and copper is improved due to diffusion welding.

  • By limiting the annealing time and temperature, uncontrolled alloy layer formation is suppressed.

Application techniques of CUPAL

    • Switchgear and apparatus construction:¬† Use as washers, inserts, and cable lugs

    • Overhead line construction: Winding band or sleeve-shaped insert in clamping connections.

    • Advantages of CUPAL:¬†Low specific weight –¬†This results in advantages for accelerated masses, such as switches.

High-frequency currents Due to the skin effect, only thin Cu coatings are required to achieve a conductivity corresponding to solid copper. This leads to the use in capacitors and components for transmission and receiving systems.

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