Aluminum Scrap Recycling by Hot Extrusion without Melting Process

Aluminum is one of the promising lightweight materials of the 21 century. Due to its good machinability, surface properties and a low density, it is often used in production of aircrafts, automobiles, transport systems and consumer products. But one of the greatest disadvantages of this material is the high energy requirement for the primary raw material production, from bauxite to Aluminum ingots. This melting process requires almost 25 times more energy than that needed for the primary steel production. Furthermore the aluminum recycling process needs as much energy as required for the primary steel production. In order to develop an energy-efficient process chain for aluminum recycling, this paper presents a method to recycle aluminum scrap of AA-7175 and AA-7475 alloys directly by a hot extrusion process without an energy intensive re-melting process. The aluminum scrap is in a first step characterized, compacted to billets and finally extruded to new profiles without melting. In this investigation, the scrap material as well as the extruded profiles is characterized by their microhardness. The final profiles from scrap are compared with regard to their strength with conventional profiles by carrying out tensile tests.