Influence of Chemistry and Direct Chill (DC) Casting Parameters on the Formation of Altenpohl Zone in 5xxx Alloys

Anodization of 1xxx and 5xxx aluminium alloyAluminium alloys sheets improves the corrosionCorrosion resistance, in addition to providing a bright and shiny appearance. These properties find application in a variety of building exterior and decorative purposes. However, Altenpohl zonesAltenpohl Zone are a typical defectDefects observed in some of the 1xxx and 5xxx series aluminium alloysAluminium alloys depending on their Fe-to-Si ratio. This defectDefects is a consequence of different ironIron bearing particles responding differently to etching during the anodizing process. Considerable research has been conducted to study Altenpohl zoneAltenpohl Zone formationFormation in 1xxx and 5xxx alloysAlloys. This paper aims to improve and extend the knowledge base where the influence of alloyAlloys chemistry, castingCasting speedSpeed, and castingCasting temperature on the formationFormation and extent of Altenpohl zonesAltenpohl Zone in a commercially available 5005 alloyAlloys has been studied. Based on the results, recommendations on chemistry and process parameters are provided to control Altenpohl zoneAltenpohl Zone formationFormation during DC castingDC Casting of rolling slabs.