Aluminum joining: Firm connection of light metals

Avoid pore formation and cracks

As an oxygen affine metal, aluminum forms a dense oxide layer that has to be cracked during welding. In addition, aluminum tends to form pores during welding, as the hydrogen solubility decreases dramatically during solidification. The chemical composition of some alloys promote the formation of cracks. These challenges must be faced with suitable strategies.

Risk of weakening

Furthermore, aluminum tends to weaken in the heat-affected zone which may significantly weaken the joint. The mechanisms that are responsible for this differ, depending on the aluminium alloy. Therefore, material-specific solutions are required.

We work together with you to master the resulting challenges. Joining processes with low or locally limited heat input are an option. Constructive solutions are also imaginable if the connection can be placed in lower stressed component areas. Finally, in some cases it is possible to reverse any weakening that has occurred.

Reduce distortion and residual stresses

Aluminum is an excellent thermal conductor and expands significantly under heat. This is why aluminum pieces distort easily during welding. In addition, high residual stresses may occur in the weld seam - with negative consequences for the stability of the joint. Processes with low or locally limited heat input can counteract the problems in this case as well.

Selecting the optimal welding process

Unfortunately, no welding process can optimally master all challenges when welding aluminum. Therefore, each welding task must be examined individually to determine which process is most suitable.

With our extensive experience in all relevant welding processes, we are able to comprehensively assess various welding tasks. Through our research partner ISF we have access to an excellently equipped joining laboratory and are able to compare competing processes directly. Alternative solutions such as brazing or adhesive bonding are also taken into account.

Choosing a partner: Alloy and filler material

Some aluminum alloys cannot be fusion-welded at all. Others tend to form hot cracks. To reliably avoid these hot cracks, it is not always sufficient to simply identify the appropriate welding filler material. Depending on the process and joining geometry, it is just as important to apply the filler material to the joint reliably and with sufficient mixing.

In the metallurgical know-how required for this, we do not only rely on our experience, but also on the most recent research results. This way, our choice of partner is always based on the latest state of research.

Finding the right parameters

Even with the right filler material, aluminum welding processes remain sensitive. For reproducible results, energy input and temperature control have to be perfectly matched.

We optimise the process parameters for each task in a structured and individual way. Based on our experience, we carry out clearly defined test series in order to determine reliable results for our customers.