PREDICTIVE TOOLS FOR IN-LINE ISOTHERMAL EXTRUSION OF 6XXX ALUMINUM ALLOYS

During the last fifty years, metal forming of aluminum alloys grew up significantly, leading to a more competitive market on which production rate and overall quality are kept higher as possible. Within the aluminum industries, extrusion plays an important role, since many industrial products with structural and even aesthetic functions are realized with this technology.

Especially in the automotive industry, the use of aluminum alloys is growing very fast, since it permits a considerable weight loss and thus a reduction of the emission. Nevertheless, the stringent quality standards required don’t allow the use of extruded aluminum alloys produced for the common building applications. An important parameter that can be used as an index of the quality of the extruded product is the emergent temperature: if the temperature at the exit of the press is kept constant within a certain limit, products with homogeneous properties and high-quality surface are obtained and the so called “isothermal extrusion” is achieved.

As extrusion industries are spread all over the world with different levels of automation and control, a universal but simple in-line tool for determining the best process condition to achieve isothermal extrusion, is of particular interest.

The aim of this work is to implement this model, that allows to evaluate the thermal gradient which have to be imposed on the billet. Several experiments have been carried out on an industrial extrusion press, and the outer temperature was recorded and compared with the simulated one to verify the model consistency.