Investigation of surface layer on rolled recycled AA5050 in relation to Filiform Corrosion

Investigation of surface layer on rolled recycled AA5050 in relation to Filiform Corrosion

Katgerman, L. (promotor)
de Wit, J.H.W. (promotor)
Terryn, H. (promotor)

Mechanical Maritime and Materials Engineering

2007-03-19

The presence of a heavily deformed surface layer (a few microns thick) on rolled aluminium alloy is understood to be one of the main reasons contributing to the Filiform Corrosion (FFC) susceptibility of the alloy. The surface layer is formed during the thermo-mechanical processing of the sheet metal, in the rolling mills. The surface layer characteristics are process dependent, i.e. depends on thermo-mechanical processing and the composition of the alloy in addition to post-production surface treatment steps. While removal of the surface layer solves the issue of FFC, it leads to economical consequences. In order to improve the FFC resistance of the aluminium alloy it is necessary to investigate the surface layer itself, its formation and evolution along the rolling mills. This thesis develops a detailed understanding of the formation and evolution of a FFC susceptible surface layer on a recycled aluminium alloy, along the rolling mills. The current trend in aluminium industry is to indulge more into recycling for cost and environmental reasons. The study of a recycled alloy, instead of conventionally investigated model and primary alloys, and the investigation of the surface layer at each and every step of the process route makes this thesis interesting and of commercial relevance. Finally some suggestions have been made to improve the FFC resistance of a rolled recycled aluminium alloy (AA5050).

surface layer
recycled aluminium
rolling mills
Filiform corrosion

http://resolver.tudelft.nl/uuid:7b5d61eb-6aba-40cb-9a24-84487e3c1eb9

978-90-6464-092-6

Institutional Repository

doctoral thesis

(c) 2007 Premendra