Friction estimation in aluminum hot extrusion is a challenging matter due to the complex state of stresses and high working temperatures expired during the process. In this paper the tribology of the aluminum extrusion process was initially investigated by means of experimental trials, then different friction models were applied in a FEM environment in order to select the most reliable one for process simulation. In the experimental trials, the influence of friction during the extrusion of an AA6060 alloy with a simple round profile was evaluated by means of the rod technique. The deforming billets were equipped with 19 markers placed in the middle plane of the billet, then they were extruded at two different process strokes and the rests were extracted from the press container so as to analyze the material flow. The rests were then milled at the middle plane to have evidence of the deformed shape of the rods and to allow the evaluation of the flow path inside the container at the different process stages. A strict monitoring of the process parameters such as press load, die and profile temperature evolution during the process stroke was also performed in order to realize a study of the tribological conditions by means of validated FEM simulations. A discussion on the strain-stress evolution of the billet-container interface during the material flow by means of the Deform lagrangian FEM code is then presented. Finally, numerical investigations for the qualitative and quantitative evaluation of tribology models are carried out with different friction formulations for providing reliable information on how to properly model friction in extrusion process simulation.

Tribology models of the aluminum extrusion process investigated by means of FEM simulation

DONATI, LORENZO;TOMESANI, LUCA
2009

Abstract

Friction estimation in aluminum hot extrusion is a challenging matter due to the complex state of stresses and high working temperatures expired during the process. In this paper the tribology of the aluminum extrusion process was initially investigated by means of experimental trials, then different friction models were applied in a FEM environment in order to select the most reliable one for process simulation. In the experimental trials, the influence of friction during the extrusion of an AA6060 alloy with a simple round profile was evaluated by means of the rod technique. The deforming billets were equipped with 19 markers placed in the middle plane of the billet, then they were extruded at two different process strokes and the rests were extracted from the press container so as to analyze the material flow. The rests were then milled at the middle plane to have evidence of the deformed shape of the rods and to allow the evaluation of the flow path inside the container at the different process stages. A strict monitoring of the process parameters such as press load, die and profile temperature evolution during the process stroke was also performed in order to realize a study of the tribological conditions by means of validated FEM simulations. A discussion on the strain-stress evolution of the billet-container interface during the material flow by means of the Deform lagrangian FEM code is then presented. Finally, numerical investigations for the qualitative and quantitative evaluation of tribology models are carried out with different friction formulations for providing reliable information on how to properly model friction in extrusion process simulation.
63
64
L. Donati; L. Tomesani
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/90796
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact