Influence of heat input on austenite/ferrite ratio in the weld zone of robotic GTAW duplex stainless steel 2205 weld bead

Abstract

This study analyzes the effect of Heat Input (HI) on the austenite/ferrite ratio in Duplex Stainless Steel (DSS) 2205 welds manufactured through the Robotic Gas Tungsten Arc Welding (GTAW) process using an Ar-2%N2 shielding gas. Macrostructural and microstructural evaluations were performed to determine the effect of HI variations on weld bead geometry, phase balance and microhardness. The results indicate that, due to nitrogen desorption at higher temperatures, increasing HI leads to a reduction in austenite content. Lower HI promotes a higher austenite content, resulting in increased hardness. The study highlights the influence of nitrogen solubility and diffusion in the melt and demonstrates that shielding gas composition and welding parameters significantly affect the final microstructure and mechanical properties of DSS welds.