Effect of thermomechanical processing on the surface roughening of AA6061

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dc.contributor.advisorKnutsen, Robert Den_ZA
dc.contributor.advisorLang, Candyen_ZA
dc.contributor.authorAphane, Abraham Kalaudiaen_ZA
dc.date.accessioned2014-07-31T11:22:21Z
dc.date.available2014-07-31T11:22:21Z
dc.date.issued2001en_ZA
dc.descriptionIncludes bibliographical references.
dc.description.abstractSurface 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.en_ZA
dc.identifier.apacitationAphane, A. K. (2001). <i>Effect of thermomechanical processing on the surface roughening of AA6061</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering. Retrieved from http://hdl.handle.net/11427/5547en_ZA
dc.identifier.chicagocitationAphane, Abraham Kalaudia. <i>"Effect of thermomechanical processing on the surface roughening of AA6061."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering, 2001. http://hdl.handle.net/11427/5547en_ZA
dc.identifier.citationAphane, A. 2001. Effect of thermomechanical processing on the surface roughening of AA6061. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Aphane, Abraham Kalaudia AB - 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. DA - 2001 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2001 T1 - Effect of thermomechanical processing on the surface roughening of AA6061 TI - Effect of thermomechanical processing on the surface roughening of AA6061 UR - http://hdl.handle.net/11427/5547 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/5547
dc.identifier.vancouvercitationAphane AK. Effect of thermomechanical processing on the surface roughening of AA6061. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering, 2001 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/5547en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Mechanical Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMechanical Engineeringen_ZA
dc.titleEffect of thermomechanical processing on the surface roughening of AA6061en_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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