In the world of welding and additive manufacturing, the choice of shielding gases can significantly influence the quality and characteristics of the final product. A recent study published in the *Journal of Advanced Joining Processes* (translated from German as *Journal of Advanced Joining Processes*) sheds light on how different gas mixtures can affect the properties of weld seams, particularly in aluminum welding. The research, led by Michael Unger from the LKR Light Metals Technologies at the AIT Austrian Institute of Technology, explores the impact of adding traces of CO2, N2, and O2 to the commonly used argon shielding gas.
Shielding gases are crucial in welding technologies as they prevent contamination and protect the metallic melt from the adverse effects of air. While argon is the go-to choice for gas metal arc welding of aluminum, Unger’s study investigates the potential benefits of incorporating other gases into the mixture. The research focuses on various properties of the weld seams, including bead geometry, microstructure, defects, and mechanical characteristics.
The study involved creating single bead on plate samples with CO2, N2, and O2 in the mixture, as well as wall geometry samples with N2 and O2. The results revealed that nitrogen in the gas mixture reduces the bead and deposit width and decreases the grain size compared to the reference sample. This grain size reduction is attributed to the formation of nitrides in the weld material, which act as nucleants for new grains. “Nitrogen is reducing the bead and deposit width and decreasing the grain size compared to the reference sample,” Unger explained. “This grain size reduction is due to the formation of nitrides in the weld material acting as nucleants for new grains.”
Energy dispersive X-ray spectroscopy confirmed the presence of these nitrides. Additionally, nitrogen was found to reduce the number of pores, although not significantly their volume fraction. A similar effect was observed with the use of O2, albeit on a smaller scale. The mechanical strength values of the resulting material were comparable to reported data, but the elongation was reduced when nitrogen was present in the shielding gas mixture.
The implications of this research are significant for the energy sector, particularly in applications requiring high-strength, lightweight materials. As Unger noted, “The characteristic mechanical strength values are comparable to reported data, but the elongation is reduced when nitrogen is present in the shielding gas mixture.” This finding could influence the choice of shielding gases in industries where both strength and ductility are critical.
The study’s findings could pave the way for more efficient and cost-effective welding processes, ultimately benefiting the energy sector. As the demand for lightweight and high-strength materials continues to grow, understanding the impact of shielding gas mixtures on weld properties becomes increasingly important. This research not only advances our knowledge of welding technologies but also opens up new possibilities for innovation in the field.
Published in the *Journal of Advanced Joining Processes*, this study provides valuable insights that could shape future developments in welding and additive manufacturing. As the energy sector continues to evolve, the findings from this research could play a pivotal role in optimizing welding processes and enhancing the performance of welded structures.