Conditions for appearance of back-end extrusion defect during extrusion of aluminum alloy ingot

The conditions for the occurrence of a back-end extrusion defect, taking into account the extrusion ratio factor during extrusion of 6061 aluminum alloy ingot are studied. Simulations of 6061 alloy rods with container diameters of 370, 520, 650 mm and extrusion ratio factor of 11.5, 13.3 and 16.7 revealed a tendency to increase axial stress by the end of the process, while when it reaches zero, the beginning of the formation of a back-end extrusion defect. It is determined that the thickness of the butt-end, in addition to the container diameter, depends on the extrusion ratio factor, while the average thickness of the butt-end, determined taking into account the container diameter and the extrusion ratio factor, is 52.7 % lower than that determined only taking into account the container diameter.