Direct recycling of AA6063 chips by hot extrusion applying pseudo porthole die

To obtain recycled aluminum from sash waste with A6063 alloy, which is used for aluminum sashes, it is necessary to perform hot extrusion after a casting process. Impurities introduced during casting constitute a problem in this process, and recycling without casting is necessary to control the effects of these impurities. The purpose of this study is to develop a recycling method for aluminum alloys, which does not involve the casting process, using hot extrusion from scrap materials, such as the cutting chips of A6063 alloy. In the extrusion process of waste materials such as cutting chips, the chips should be kept in close contact. To achieve this, a pseudo porthole die that provides a large shear deformation is used as the die shape for the extrusion process. The chips were compression-filled in advance to determine the filling ratio, and then extruded using a pseudo porthole die. The use of a pseudo porthole die resulted in an extrusion force 1.5 times greater than that of a solid die. A simulation of the shear strain and observation of the stress imparted to the material by the pseudo porthole die revealed that the flow-diverting and crimping mechanisms inside the pseudo porthole die resulted in a large amount of stress on the material. No defects were observed on the extruded product surface of the chip material produced using the pseudo porthole die. Four types of chip materials with different densities were used to examine the effect of the chip material density. We found that defects did not occur on the surface of the product when the density of the chip material was 2.5 g/cm³ or higher.