The present research work was to investigate the possibility of hot 'extrolling' of aluminium alloys. 'Extrolling' is a new metal forming process intended for extrusion of continuous length of prismatic sections having complex shapes. An apparatus using a die of special shape and rolls with roughened surfaces was designed and used for the experiments. Billets of commercially pure aluminium with maximum size of 18.0 nun thick, 25.0 mm wide and 125.0 mm long, heated to temperatures between 450°C and 575°C were tested. The reduction in area up to 80 per cent and having cross-section areas of 80.0 mmi to 85.0 mm2 were 'extrolled' in various shapes. The surface roughness of products was within 0.10 to 0.15 µm CIA along their lengths. Dimensions along the length were within an accuracy of 0.050 mm in width and 0.025 mm in thickness. The results of hardness and tensile tests revealed almost no difference when compared with similar results from rolling, extrusion or drawing processes. A theoretical work was developed using an existing theory for rolling which included the application of front and back tensions. In the present theory, front and back tensions were replaced by compressive forces due to extrusion and back-push forces. A computer programme to solve the extrolling problem was developed which included both extrusion and rolling to give estimates of roll forces, local shear stress, pressure distribution in arc of contact and maximum pressure at neutral plane. A mathematical model using the finite element method was developed for the numerical solution to simulate the process with high friction and high temperature values. A reasonable agreement was obtained when theoretical and experimental results were compared.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:637244 |
| Date | January 1983 |
| Creators | Hatakeyama, K. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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