Computer Simulation of Mannesmann Piercing of Aluminium Alloy Ingots

The piercing of aluminium ingots (made by permanent mold gravity casting) is done in a Mannesmann rolling mill with supporting shoe using plugs of various shapes with a spherical working part: an entire plug, a plug with cavity, and a hollow plug. The calibrating segments of the plugs have identical diameters. The piercing is carried out at an ingot temperature of 400°C. The influence of the plug shape on the variation in the outer hollow shell diameter and wall thickness along the shell length, as well as shell density over the length, is investigated. Hollow shells were cut into 15 equal rings to measure density using hydrostatic weighing. Experimental investigations are simulated with the help of the finite-element method (FEM) computer software. Ingot fabrication by permanent mold gravity casting is simulated using the ProCAST software and piercing—using the QForm software. The variation in the hollow shell diameter, wall thickness, and shell density along the length is also evaluated by computer simulation. Experimental and simulation data are compared to verify the adequacy of acquired models in the QForm. The difference in density does not exceed 2% and, for hollow shell dimensions, 20%. These results make it possible to establish the influence of the piercing plug shape on the accuracy of the shells and their density. It is most preferable to use a hollow plug or a plug with a cavity from the viewpoint of dimension accuracy of fabricated shells. Each of these piercing schematics makes it possible to densify the entire hollow shell volume to the true density, except for the near-edge domains, where the density is lower by 1%.