Optimization of FCA and MIG welding parameters for AISI-1045 Steel

Abstract

Welding is a vital industrial process for joining metals and thermoplastics, with Metal Inert Gas (MIG) and Flux Cored Arc (FCA) welding widely used due to their versatility and effectiveness. This study optimized FCA and MIG welding parameters for AISI 1045 alloy steel using Response Surface Methodology (RSM) via Central Composite Design (CCD) L20(5)3 in Minitab 20. The parent material and weldments were characterized through standard testing methods. X-ray fluorescence (XRF) analysis confirmed the material as galvanized medium-carbon steel containing 0.376% carbon and 22–25% iron, while revealing a crystalline structure with features indicating crystal size and possible defects. Mechanical testing showed UTS values for welds were generally lower than the base metal, high joint efficiencies confirmed good bonding. Also, optimal conditions for hardness (FCAW: 4.6 kgm/s, 73.2 A, 28 mm; MIG: 8 kgm/s, 73.2 A, 24.6 mm), UTS (FCAW: 10 kgm/s, 73.2 A, 26 mm; MIG: 8 kgm/s, 73.2 A, 24.6 mm), and impact strength (MIG: 6 kgm/s, 106.8 A, 26 mm), with gas flow rate as the dominant factor and refined microstructures confirming superior weld quality and bonding. Both welds were free from porosity and cracks, underscoring the importance of parameter optimization for superior weld quality and mechanical performance.