## 2 Materials and Methods  
The main aim of this research was to determine the welding possibilities of solid-state-recycled EN AW 6082 aluminum alloy. This alloy was selected because it is an aluminum alloy in the 6 xxx series (Al-Mg-Si), which is well-known for its strength, good weldability, and corrosion resistance. It has a high strength-to-weight ratio which makes it advantageous in applications where weight reduction is critical, such as shipbuilding. The alloy has good corrosion resistance making it suitable for structural applications in marine environments. It is suitable for welding, especially with MIG and TIG methods, which are commonly used in shipbuilding and other structural welding. Table 1 provides the chemical composition of the batch of selected aluminum alloy material. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Mg\%** & **Si\%** & **Fe\%** & **Mn\%** & **Cu\%** & **Cr\%** & **Ni\%** & **Zn\%** & **Others\%** & **Al\%** \\ \hline
0.78 & 0.669 & 0.825 & 0.486 & 0.075 & 0.029 & 0.006 & 0.032 & Bal. & 97.080 \\ \hline \end{tabular}
\end{table} 
Table 1: Chemical composition of the EN AW 6082 aluminum alloy batch (%wt.). The alloy was machined on the Spinner VC 560 vertical machining center using a depth of cut, cutting speed, and feed rate of ap = 1 mm, vc = 120 m/min, and f = 0.1 mm/tooth, respectively. To avoid contamination with cooling and lubrication fluids, a dry-face milling process was performed. The used tool was composed of the WALTER (Walter AG, Tubingen, Germany) tool holder with the designation M4132-032-W32-02-09 and the SDHT09T304-G88 WK10 cutting insert. The obtained aluminum chips were weighed to a mass of 150 g and compacted in a cylindrical steel tool that was 38 mm in diameter. Compaction was performed on a 1 MN universal hydraulic press with a compaction force of 450 kN. The force was measured using the HBM load cell C6A 1 MN sensor (HBM, Darmstadt, Germany). After the compaction step, a direct hot extrusion process was utilized. Chip-based billets were preheated for 20 min at 450 \({}^{\circ}\)C, placed in an extrusion cylinder with a diameter of 40 mm and directly hot extruded at 400 \({}^{\circ}\)C with a 7.1 extrusion ratio. A flat die with an orifice diameter of 15 mm was used in the extrusion process, and 15 mm diameter chip-based solid bars were produced. A schematic representation of the utilized direct hot extrusion process is presented in Figure 1a. The beginning part of the extruded profile was discarded because of insufficient pressure and visible individual chips. The hydraulic press punch speed was 1 mm/s. The temperature was controlled using the Omron ESCC temperature regulator (Omron Corporation, Kyoto, Japan) and a G3 PE-225B DC12-24 relay (Omron Corporation, Kyoto, Japan). The extrusion pressure was measured with an HBM P15 RVA1/500B pressure gauge transducer (HBM, Darmstadt, Germany). To increase the solid-state-recycled specimen's quality and to obtain a 4 mm thick aluminum sheet for welding processes, a hot rolling process was performed (Figure 1b). Before rolling, the extruded bars were preheated to 400 \({}^{\circ}\)C. After the aluminum sheets were obtained, semi-automatized metal inert gas and hand tungsten inert gas welding were performed (Figure 1c). The same welding procedure with commercial aluminum alloy sheets was also performed. The commercial alloy was obtained in a 15 mm diameter bar in an extruded state in the T6 condition. Following the same production procedure to enable a fair comparison, the obtained bars were annealed at 400 \({}^{\circ}\)C for 20 min and then hot rolled at 400 \({}^{\circ}\)C to obtain the same sheets as made for the solid-state-recycled sheets. To perform MIG welding with precision and better parameter control, a semi-automatized process was performed with the linear moving device in the weld direction  
Figure 1: Schematic solid-state recycling and welding process overview: (**a**) direct hot extrusion; (**b**) rolling; (**c**) arc welding (MIG and TIG). and a fixed welding speed set at 8.93 mm/s.