Aluminium

In recent decades, increasing importance has been attached to the use of materials with a high strength-to-weight ratio in the automotive industry. In this context, aluminium has become increasingly important and the demand for this material is expected to increase further in the coming years. Alloy metal is solidly positioned to be the answer to today's challenges and trends. In this context, the use of aluminium among the main OEMs has grown exponentially, especially the 6xxx and 5xxx series, due to the fact that some aluminium alloys present similar resistances to some mild steels (low carbon steel) with a weight three times lower.

However, the reality is that aluminium is not steel and its behaviour and formability is different. This does not mean that aluminium is an unsuitable metal, it is simply different and like any metal, it has some advantages and some disadvantages. The key is to understand its behaviour and characteristics before it is processed.

The main points to consider when forming aluminium parts are:

It is harder to cold-stamp than steel, because it has a low formability, reduced stampability and higher friction.
It has an affinity for steel (tools) and galling (material adhesion) which can be a problem if the lubricants used are not suitable.
It presents a greater elastic recovery after forming (springback).
The mechanical properties of some alloys are not stable and can vary over time.

These particularities of aluminium make it very important to design the die adequately and to take care of the working conditions: lubrication, working pressures, etc.

In addition, another key aspect of aluminium stamping is the variation in properties that the material undergoes from its manufacture. In particular, some aluminium alloys tend to harden naturally and/or by deformation.