Animation: Drawing of Aluminiumtubes
Depending on the application, tubes may require subsequent drawing following the extrusion process. Examples of this are:
- a requirement for a high degree of dimensional control and/or the need for tight tolerances,
- where the final outside diameter and/or wall thickness of the extruded tubes can only be achieved by subsequent cold drawing,
- where the final mechanical properties for non-heat treatable alloys are to be achieved by strain hardening (drawing),
- where special requirements exist for the microstructure of the tubes.
If any of these requirements are necessary, one or more controlled drawing steps are performed following extrusion. Through a series of several drawing operations, very small wall thicknesses (0.5 mm) can be achieved. If necessary, the effects of cold work from the drawing process can be reversed by heat treatment, known as annealing. The cycle of drawing and annealing may be repeated many times in order to achieve the final dimensions. Cold drawing may be applied to seamless extruded tubes and porthole extruded tubes alike. All commercially available aluminium alloys and high strength aluminium alloys can be processed using the cold drawing process. The following tables are a guide to the dimensional ranges we offer: