5. Choosing the right alloy

Pure aluminium is relatively soft. Its strength can be increased by alloying or cold working. Most of the aluminium that is commercially available is therefore alloyed with one or more other elements.

The resulting alloy has different properties depending on which alloying elements are added. This makes the choice of alloy an important matter.

Hydro uses a long-established international system for identifying aluminium alloys, in which the first digit in a four-digit alloy code identifies the major alloying element. The European standard uses the same codes.