COMPUTER SIMULATION OF THE COMBINED ROLLING-EXTRUSION PROCESS FOR OBTAINING RODS FROM ALUMINIUM ALLOY 7075

Abstract

This article presents the results of numerical modelling of the combined rolling-extrusion process for producing rods of various diameters from alloy 7075. A 7075 ingot with a cross section of 14×14 mm and a length of 200 mm was used as the initial billet. The processing temperature was 450°C, and the diameters of the resulting rods were 5 and 9 mm. The geometric parameters of the tool, as well as the choice of roll rotation speed (4 and 8 rpm), are analysed. An analysis of the temperature conditions of the process, deformation conditions, and trajectory-velocity conditions is performed. It was found that with an increase in the drawing ratio from 4.0 to 12.9, the temperature of the rod at the exit from the die increases by an average of 80 - 100°C. Also, with an increase in the roll rotation speed in the deformation zone, the temperature increases by an average of 60°C. The maximum flow rate for a drawing ratio of 4 was 125 mm s-1, while for a drawing ratio of 12.9, the maximum flow rate was 399 mm s-1. When using rolls with different rolling diameters and low drawing ratios, incomplete filling of the groove will occur. At drawing ratios greater than 10, the groove is filled.