Direct recycling of 1050 aluminum alloy scrap material mixed with 6060 aluminum alloy chips by hot extrusion

In this paper, a method for the direct recycling of aluminum scrap by hot extrusion is investigated. 1050 aluminum alloy material in the form of pins remained as scrap after a lateral extrusion process and was mixed with 6060 aluminum alloy chips resulting from a turning operation. Contrary to the conventional method of re-melting aluminum scrap to produce secondary aluminum, this aluminum scrap+chip mixture was cold compacted into billets and hot extruded at 500°C to full rectangular profiles. The extruded profiles were examined by tensile tests and microstructural investigations and compared to the conventionally extruded profiles from as-cast material. It was shown that not only the aluminum chips but also the aluminum scrap material can be recycled directly by hot extrusion, which requires only ~10% of the energy required for recycling by re-melting. Also, the profiles extruded from billets containing 1050 aluminum alloy scrap with and without cooling lubricant were compared and a deteriorating effect was determined.