Remelting and Addition of Alloy Components
This chapter discusses our scientific understanding of alloying. Class I alloy additions have a melting point lower than the bulk melt temperature, whereas class II additions have a melting point higher than the bulk melt temperature. This means that magnesium is a class I element when added to aluminium, and silicon and manganese are class II alloy additions. An energy conservation model for melting is presented and compared to measurements. A numerical model is presented for continuous feeding and melting of aluminium plates into aluminium melt. For class II alloy additions it is shown from the literature that the melting rate can be strongly affected by the formation of intermetallic phases during the melting process. Therefore, it is virtually impossible to put up a general model for the melting of these types of alloying elements. Safety regarding alloying operations is also addressed.