The aluminium AA1050 alloy, known as commercially pure aluminium, contains 99.5% Al, together with Fe and Si as major alloying elements. During fabrication of aluminium substrates for lithographic printing plates in Bridgnorth Aluminium Ltd, the AA 1050 aluminium alloy proceeds through various stages of thermomechanical processing, with the conditions at each processing stage influencing the microstructure of the final coil. Because of its specific gravity, tensile strength, surface performance and coating adhesion behaviour, the AA 1050 aluminium alloy is one of the preferred materials for offset printing, which has been the dominant printing process for years. During manufacturing of the offset plate, the AA 1050 alloy is subjected to alkaline etching, electrograining and anodizing. Reactivity of the material to those chemical and electrochemical processes depends on various alloy properties, the thickness and composition of oxide film over the macroscopic alloy surface, cold work applied and the presence of second phase particles, which influence properties and quality of the final product.During the project, the main objectives were to understand the process in the production of the final product from slab to coil as well as to investigate some microstructural changes during the following stages of the production process and, finally, the performance behaviour of the final product.The set of experiments, including microstructural observation and electrochemical tests, has been developed to investigate the AA 1050 aluminium sheet in accordance with the objective of this study. Four homogenisation trials in the industry environment were performed to enable sample collection from the real production line; also, samples from each processing stage were examined with the special attention paid to those collected during the plant experimental homogenisation trials. It was found that the microstructure of the aluminium changed throughout the different production stages and influences the material response in the alkaline solution used for etching. Furthermore, the conditions of homogenisation (time and temperature) have impact on the properties like the electrochemical behaviour in alkaline and acid solutions, as well as the microstructure of the final aluminium sheet. Differentiation between the behaviour of final gauge samples was possible in terms of characterisation of the second phase particles characterisation (distribution and composition) present in the resultant alloy product.

Recrystallisation is an important topic in the metal industry since the process may drastically alter the properties of the materials subjected to it. By controlling the recrystallisation process, the material properties can be adjusted as desired, which could lead to stronger materials and hence lighter constructions, decreasing our material consumption. This is currently regulated using softening curves complied from tensile tests, a method which does not show the degree of recrystallisation of a metal. This thesis work therefore explores the possibility to characterise the recrystallisation process using in situ X-ray diffraction, XRD, during heating.The method proposed is using in situ heat treatments of aluminium samples combined with XRD measurements. The results show that it is possible to follow the recrystallisation process of rolled aluminium alloy AA3003 by using in situ XRD during heating, a discovery that could facilitate development and understanding of new materials. Nevertheless, further investigations of the subject is required before the method will be profitable. / Rekristallisation är ett viktigt ämne inom metallindustrin, detta eftersom materialegenskaper drastiskt kan förändras under rekristallisationsprocessen. Genom att kontrollera rekristallisationsprocessen kan materialegenskaper skräddarsys efter applikation. Även starkare material kan tillverkas och därav kan lättare strukturer konstrueras och på så vis minskar även materialåtgången. Idag regleras rekristallisation med hjälp av mjukningskurvor sammanställda genom dragprov, en metod som inte kan visa rekristallisationsgraden av en metall. Detta examensarbete utforskar möjligheten att karaktärisera rekristallisationsprocessen genom att använda in situ röntgendiffraktion, XRD, under värmningsprocessen.Den framtagna metoden inkluderar in situ värmebehandlingar av aluminiumprover i kombination med XRD-mätningar. De erhållna resultaten från experimenten visar på att det är fullt möjligt att följa rekristallisationsprocessen av aluminiumlegering AA3003 med in situ XRD, en upptäckt som kan komma att underlätta vid utveckling och förståelse av legeringar och nya material. Dock krävs fortsatta studier i ämnet innan metoden kan anses vara lönsam.