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Effect of thermomechanical processing on the surface roughening of AA6061

Includes bibliographical references.

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Bibliographic Details
Main Author: Aphane, Abraham Kalaudia
Other Authors: Knutsen, Robert D
Format: Thesis
Language:English
Published: Department of Mechanical Engineering 2014
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access_status_str Open Access
author Aphane, Abraham Kalaudia
author2 Knutsen, Robert D
author_browse Aphane, Abraham Kalaudia
Knutsen, Robert D
author_facet Knutsen, Robert D
Aphane, Abraham Kalaudia
author_sort Aphane, Abraham Kalaudia
collection Thesis
description Includes bibliographical references.
format Thesis
id oai:open.uct.ac.za:11427/5547
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:33:21.255Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2014
publishDateRange 2014
publishDateSort 2014
publisher Department of Mechanical Engineering
publisherStr Department of Mechanical Engineering
record_format dspace
source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/5547 Effect of thermomechanical processing on the surface roughening of AA6061 Aphane, Abraham Kalaudia Knutsen, Robert D Lang, Candy Mechanical Engineering Includes bibliographical references. Surface roughening is an undesirable feature in materials. This work investigates the cause of surface roughening in four plates of AA6061 with different thicknesses (Le. 6 mm, 9 mm and two 12 mm). Production of these plates requires thermomechanical processing of the cast slab via a two stage process, namely the initial rolling stage on a hot roughing mill (HRM) and final rolling on the hot finishing mill (HFM). After rolling. the plates are levelled by a tensile stretching process and it is during this process that surface roughening of the plates can arise. Three of these plates exhibited severe roughening and the other 12 mm thick plate exhibited mild surface roughening during the stretch levelling process. Investigations looked closely at how the cause of surface roughening is related to the thermomechanical processing. The four products studied exhibited different degrees of surface roughening during uniaxial tensile deformation. Detailed investigation of the microstructure of these four products was carried out. It was found that the plates that exhibited severe roughening had large flat and elongated grains at the surface. It is the rotation of these surface grains during tensile deformation that was thought to be inducing the roughness in the material. The microstructure evolution was explained relative to the thermomechanical history of the plates. Plane strain compression (PSC) tests were used to simulate the thermomechanical processing cycles on the HFM. Large strain rates used in the industry were compensated with an adjustment in temperature so that an equivalent Zener-Holloman parameter (Z) could be achieved. The microstructure of the PSC specimen was characterised using the electron back scattered technique. It was found that the grain size increases with a decrease in the value of Z. 2014-07-31T11:22:21Z 2014-07-31T11:22:21Z 2001 Master Thesis Masters MSc http://hdl.handle.net/11427/5547 eng application/pdf Department of Mechanical Engineering Faculty of Engineering and the Built Environment University of Cape Town
spellingShingle Mechanical Engineering
Aphane, Abraham Kalaudia
Effect of thermomechanical processing on the surface roughening of AA6061
thesis_degree_str Master's
title Effect of thermomechanical processing on the surface roughening of AA6061
title_full Effect of thermomechanical processing on the surface roughening of AA6061
title_fullStr Effect of thermomechanical processing on the surface roughening of AA6061
title_full_unstemmed Effect of thermomechanical processing on the surface roughening of AA6061
title_short Effect of thermomechanical processing on the surface roughening of AA6061
title_sort effect of thermomechanical processing on the surface roughening of aa6061
topic Mechanical Engineering
url http://hdl.handle.net/11427/5547
work_keys_str_mv AT aphaneabrahamkalaudia effectofthermomechanicalprocessingonthesurfacerougheningofaa6061