WEB Obtaining tubes with high mechanical properties from used aluminum beverage cansTuesday (22.09.2020) 15:55 - 16:10 Z: Special Symposia I Part of:
In several countries, the recycling of used beverage cans (UBC) is a closed-loop process where cans are collected to be transformed into new beverage cans; in countries where cans are not produced actions only include its collection and exportation, which together with the extremely low price of UBC, discourage recycling. The main reason that limits the use of UBC for the manufacture of another product is its variation in chemical composition and the presence of iron that can form insoluble constituents. This generates intermetallics on the product and thus its mechanical properties decrease considerably. In this work, a process that allows to obtain tubes produced exclusively from UBC is presented. The final product has mechanical properties that make it suitable for structural use.
The process started with the de-coating and melting of the UBC in an induction furnace. The molten bath was agitated to incorporate the slag into it. From this process, a billet was obtained, which was then hot extruded to obtain tubes that were finally heat treated. For the tubes extrusion, an easy-to-implement, scalable, and low-cost process was developed. The reason for this is to contribute to the development of small and medium enterprises in developing and/or undeveloped countries, promoting the collection of UBC, and to strengthen the small-scale metal-mechanical industry.
The main result from the point of view of the materials engineering comes from metallographic analysis of the tubes. It was observed that the iron intermetallics are transformed during the heat treatment, which considerably increases the mechanical properties of the material. The properties obtained are suitable for its use in structural applications and are comparable to those of AA6063. By means of the developed process, the welding of material fluxes during extrusion was achieved, validating the implementation of the process.
An attractive method to the industry, easy to implement and scalable was developed to recycle UBC, promoting their collection. The obtained product has higher properties than typical aluminum alloys without the need of a large investment.