Experimental and numerical analysis of the friction condition in the die bearing during aluminum extrusion

摘要

Of the various boundary conditions that are relevant for the correct modeling of the extrusion process the realistic representation of the friction in the die is important since it has a significant influence on the profile temperature, the strain and strain rate distribution in the die. In order to investigate the influence of the die geometry, respectively the geometry of the die bearing, a four-hole die with exchangeable inserts was designed. Thereby each of the four inserts was equipped with a thermocouple to record the profile temperature at the die bearing. Through the combination of different die bearing geometries (cylindrical, 0.5° closing, 1° closing, 0.5° opening) in the same die the influence on the extrusion speed and profile temperature could be evaluated with the exact same extrusion conditions. The observed differences in the temperature and speed in respect to the geometry of the die bearing where evaluated and implemented in a FEM simulation in order to validate the underlying friction model.