Processing of aluminium - diversely shaped
Processing of aluminium takes place mainly in rolling mills, extrusion plants or shape-casting foundries. Of importance here are the requirements with respect to shape and the subsequent application. Only a small force is required to deform aluminium plastically and virtually every joining technology can be used with the metal. Thanks to the latest technology, aluminium can also be welded and permanently bonded more easily, thus opening up even more fields of application. Photo credit: AMAG
Rolled products – sometimes thinner than a human hair
In hot or cold rolling mills or foil mills, aluminium ingots are rolled to plate, sheet, strip and foil, sometimes only six thousandths of a millimetre thick and thus much thinner than a human hair. Rolled products are used for applications such as lithographic sheet for the printing industry, as aluminium foil or as body sheet in the car industry.
The use of special aluminium lithographic plates in the printing industry allows high running times to be achieved during printing. Intensive development work in this field has resulted in the smoothest, strongest and most durable printing-plate alloy currently available commercially.
Extruded products – get applications into shape
Rod and bar, tube and profiles, for example for façade systems, windows and doors in the building and construction industry or components for the car industry, are produced mainly by extrusion. Very complex cross-sections and different wall thicknesses are sometimes needed. The starting point for production are cast billets, which are heated and forced through dies with correspondingly sized apertures at high pressures. Extruded products are characterised by high dimensional accuracy and a good surface finish.
Drawn products are used for applications such as the manufacture of fasteners like screws, rivets, nails, pins and bolts, in bending and forming technology, as closures (staples and clips for tea bags, tubing, etc.) or in so-called ‘vapour deposition’. High-grade refined or unalloyed aluminium wire is used to metallise film for packaging and capacitors as well as for shaped components. The starting materials are extruded rod and bar and tube or extruded, rolled or cast drawing stock (mostly cast and rolled wire in the case of unalloyed or lowly alloyed aluminium).
Castings – for getting into shape quickly
Finished components can be produced directly using shape casting and there are hardly any limitations on possible shapes. Various casting processes, such as sand, pressure die and chill casting, are used depending on the product, the size of the production run and the dimensional accuracy needed. The car industry is the most important customer group for shape-casting foundries. Cast products are even used there in areas that demand a high level of reliability, such as chassis parts.
Innovative alloys – for optimal protection
There are a number of alloying elements that make aluminium more resistant and stronger. There are also special alloys, such as lithographic plates made from high-grade aluminium strip and alloys for the printing industry, where the aim is visual upgrading.