Impact of Scrap Impurities on AlSi7Cu0.5Mg Alloy Flowability Using Established Testing Methods

In view of the increasing demand for secondary aluminum, which is intended to partially replace the very energy- and resource-intensive primary aluminum production, effective treatment methods can maintain the high quality level of light metal castings. The transition from a linear to a circular economy can result in an accumulation of oxides or carbides in aluminum. Therefore, melt purification is crucial, especially as foundries aim to increase the use of often dirty end-of-life scrap. Nonmetallic inclusions in the melt can impact its flowability and mechanical properties. As the purity of the melt increases, its flow length also tends to increase. Available assessment methods like reduced pressure test or K-mold are capable of ensuring high levels of purity. This study demonstrates the implication of inclusions originating from dirty scrap. An experimental test run deals with various scrap contents in an AlSi7Cu0.5Mg alloy and shows correlations between impurity and performance, expressed by flowability and mechanical properties. These performance indicators have been connected to inclusion and porosity rates. In conclusion, these findings emphasize the need for further extensive research on contaminants in the field of scrap melting and the development of methods for easy-to-handle assessment methods.