THE EFFECT OF MIG (METAL INERT GAS) WELDING CURRENT VARIATIONS ON THE MICROSTRUCTURE, IMPACT TOUGHNESS, AND TENSILE STRENGTH OF A1100 ALUMINUM

M. Roid, Yoyok Winardi, Rizki Dwi Ardika
Mechanical Engineering Study Program, Universitas Muhammadiyah Ponorogo | Email: 17roid@gmail.com
ABSTRACT

AA1100 aluminum is a non-ferrous material widely used in the manufacturing industry due to its low density, good corrosion resistance, and high thermal and electrical conductivity. However, the mechanical properties of AA1100 aluminum are relatively low, making the quality of the welded joint a crucial factor in its application. One of the primary parameters influencing MIG (Metal Inert Gas) weld quality is the welding current, as it is directly related to heat input, microstructure formation, and the mechanical properties of the joint. This study aims to analyze the effect of varying MIG welding currents on the microstructure, impact toughness, and tensile strength of AA1100 aluminum. The theoretical framework of this research covers the concepts of MIG welding, the influence of current parameters on the welding thermal cycle, the formation of the weld metal zone, the Heat-Affected Zone (HAZ), and the base metal, as well as the relationship between microstructure and mechanical properties. An experimental method was employed using welding current variations of 100 A, 130 A, and 160 A. The material used was AA1100 aluminum with ER5356 filler wire, joined using a single V-groove butt joint configuration. Data were obtained through visual inspection of the weld bead, microstructural analysis using an optical microscope, tensile testing in accordance with ASTM E8/E8M standards, and Charpy impact testing based on ASTM E23-16 standards. The research results indicate that variations in welding current significantly affect the quality of the welded joint. A welding current of 130 A yielded the best weld bead quality, characterized by fewer defects, a more homogeneous and fine-grained microstructure, the highest tensile strength (66.35 MPa), and the highest impact toughness (3692.05 kJ/m²). Conversely, a current of 160 A resulted in coarser grain growth and an increased likelihood of defects due to excessive heat input, thereby degrading the material's mechanical properties. Thus, a welding current of 130 A represents the optimum condition for achieving the best combination of microstructural quality, tensile strength, and impact toughness in AA1100 aluminum welded joints.

Keywords: AA1100 aluminum, MIG, welding current variation, microstructure, tensile strength, impact toughness.