Untersuchung der Einflussparameter beim vertikalen Strangguss von 6xxx-Aluminiumlegierungen

Aluminum is a versatile material used in numerous industrial sectors, with extruded products in particular placing high demands on material quality. As the use of secondary aluminum grows, stable and controlled process management is becoming increasingly important, as fluctuations in scrap composition can have a negative impact on the quality of the melt. This thesis deals with the investigation of influencing parameters in the vertical continuous casting of 6xxx alloys. First, the basics of aluminum recycling and the metallurgical characteristics of secondary aluminum production are explained. This is followed by a detailed description of the industrial manufacturing process for extrusion billets from a 6xxx alloy in vertical continuous casting at the Alu-met company. A comprehensive description of the equipment required to produce aluminum extrusion billets is then provided. The subsequent experimental part examines the relationship between temperature differences in the casting systems for different billet diameters and the resulting number of inclusions. Temperature measurements are taken during the casting process, and sample discs are then taken from billets of different diameters. The evaluation of material quality using ultrasonic testing enables the quantification of the number and size of defects. In addition, detected inclusions are analyzed using scanning electron microscopy to identify their chemical composition and possible formation mechanisms. The results show that a temperature gradient present specifically at the casting table for billets with a diameter of 254 mm has an influence on the number and distribution of defects along the bolt axis. This analysis also allows conclusions to be drawn about possible causes of inclusion formation in the production process.