Werkstoffkundliche und verfahrenstechnische Einflüsse bei der Herstellung von Aluminium-Aerosolspraydosen
Research output: Thesis › Diploma Thesis
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Abstract
During the production of shaped aerosol cans made from pure aluminium (AA 1050) sometimes local necking occurs. The frequency of failure occurrence lies between 0,04 % and 0,1 %. Goal of this work is to determine the cause of defect and to find strategies to minimize the defect frequency. The whole production process is investigated by metallographic techniques and the formability of the material after backward impact extrusion is determined. Also the true stresses and strains during the can-forming process are established. Further explored processing steps are hot- and cold rolling and strip casting on a rotary caster. The formability of aluminium after impact extrusion is very low and there were no metallurgical causes found during metallographic investigations. The determination of the circumferential strain during tube expansion shows that the maximum strain is significantly higher than the elongation of the material in the uniaxial tensile test. By varying the equivalent plastic strain in hot- and cold rolling process it was found that the amount of deformation of the cast structure has more influence on the formability limit of pure aluminium than the degree of recrystallization. Increasing the solidification rate at the casting wheel leads to a shrinking of the equiaxed solidification zone due to a widening of the directional solidification zones on the top and bottom side of the casting strip. At high solidification rates a constitutional undercooling is nonexistent and so the formation of dendritic structures is suppressed. This causes a lesser amount of grain boundaries in the centre of the casting strip which improves the workability of the aluminium. For a reduction of the defect frequency new technologies for the cooling of the casting wheel and the tube expansion process have to be considered.
Details
Translated title of the contribution | Material and processing induced influences on the production of shaped aerosol cans made from aluminium |
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Original language | German |
Qualification | Dipl.-Ing. |
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Award date | 26 Mar 2010 |
Publication status | Published - 2010 |