Various properties of a metal are improved through the addition of other basic metalllic substances. In the case of aluminium for profiles, magnesium and silicon are the most important alloying minerals. Others are copper, zinc, manganese, titanium, bismuth and chromium.

An element that occurs abundantly in the earth’s crust, incorporated in many dif-ferent minerals, including bauxite. The term aluminium commonly also covers the alloys that are used in technical contexts.

An electronic surface-treatment method that converts the metal on the surface to aluminium oxide. The thickness of the oxide layer normally ranges between 5 and 25 µm (micrometers, commonly referred to as “my”). One µm is equal to one thousandth of a millimeter.

The mineral most worth mining to recover aluminium. Bauxite contains between 20 and 30 percent aluminium and occurs mainly in tropical areas close to the equator. Australia, Brazil and Jamaica, for example, have large deposits. Bauxite is mined in open pits. The name derives from the Les Baux mining area in southern France.

Circumscribed circle
The diameter of the circle within which the profile is housed is a measurement of the profile’s size. The term is generally used to indicate the limits of a certain press.

The method used to produce metal pro-files, primarily those made of aluminium. Copper, brass and magnesium can also be extruded, but with greater difficulty.

Heat-treatable alloy
A type of alloy that acquires its strength through precipitation-hardening (heat-treatment) and which is used for profiles. Alloys that are not heat-treated acquire their strength through increased additives or cold-rolling and are used primarily for sheeting, strip and foil.

A heat treatment that distributes the alloy elements evenly in the material.

To produce profiles, the smelter plant casts the aluminium alloy to form round ingots whose diameter is adapted to each press, and in lengths of six to seven meters.

Natural anodizing
Anodizing without adding color. Since the aluminium oxide is transparent, the natural surface is visible.

The distance a pen moves when following the outer contour (outer perimeter) and inner contour (inner perimeter) of a profile. Generally expressed in millimeters. The perimeter constitutes the basis for calculating the surface for surface treatment (perimeter x length).

Press force
The power with which the metal is pressed through the tool. Power is now designated in MegaNewtons (MN); formerly tonnes were used. Ten MN is equal to approximately 1,000 tonnes. Sapa’s largest press, P5, develops a maximum power of 65 MN.

Primary metal
Metal produced from aluminium oxide, which in turn is produced from bauxite. In Sweden there is one primary smelter plant, Kubikenborg Aluminium (Kubal) in Sundsvall.
Secondary metal
Remelted metal from product or process scrap.
Semi-hollow profile
A solid profile with a cavity that is almost closed. May also require a hollow die or the redesigning of the profile.
Solid profile
In contrast to a hollow profile, a solid profile has no cavity.