Weld claddings of Hastelloy C276 using the GTAW cold wire feeding process

The primary goal of this study was to analyse the microstructural and microchemical characteristics of dissimilar Hastelloy C276 weld claddings on ASTM A516 Gr. 60 steel. These claddings were produced using the GTAW cold wire feed process with varying heat input parameters. We utilised several analytical techniques, including scanning electron microscopy, transmission electron microscopy, X-ray energy-dispersive spectroscopy, and X-ray diffraction, for our microstructural and microchemical analyses. Our results demonstrated that adjusting the heat input and wire feed speed reduced the dilution level of the Hastelloy C276 weld cladding from approximately 18% to approximately 8%. This low dilution level, achieved by a single deposition layer, offers significant productivity benefits for the industry. Despite rapid cooling, microsegregation occurred, precipitating secondary phases, notably Mo-rich P-, μ- and σ- topologically close-packed phases in the interdendritic region. Pitting corrosion resistance was evaluated in accordance with ASTM G48 (Method C), showing a critical pitting temperature (CPT) of 70-75 °C for a medium dilution sample, while the lowest dilution sample showed a CPT of 65-70 °C. These findings have practical implications for industry, particularly for process optimisation and quality control.