Análisis de la influencia de los parámetros de soldadura en la resistencia a la tracción de juntas soldadas de aluminio grado estructural mediante proceso SMAW

Abstract

Aluminum and its alloys with copper or zinc are continuously being developed due to their favorable advantages, such as being lightweight while providing comparable or even superior strength to structural steel. This project aims to determine the parameters that influence tensile strength and analyze the changes in different zones through metallography in welded joints of structural-grade aluminum using the SMAW welding process. The welded joints were performed on 7075-T6 aluminum. The study involved theoretical and practical investigations to select the parameters that could affect the mechanical strength and modify each accordingly. The determined parameters include the current type, polarity, amperage, and plate separation. The welding process was complex due to the interaction between aluminum and oxygen, leading to contamination. Ultrasonic testing was conducted on the weld beads following the UTPA ASME VIII standard to identify potential discontinuities. The welded specimen with the highest tensile strength was achieved using alternating current, an amperage of 100, and a specific plate separation. Ultimately, the recommended parameter combination involves common types and root openings variations. It was concluded that the improper fusion between the electrode and the base material directly affects the joint's inadequate resistance. This is mainly attributed to the rapid contamination of the material with oxygen, leading to the formation of aluminum oxide and subsequent internal porosity in the weld bead due to the oxide's melting point.