Aspects on carbides transformations of Fe-based hardfacing deposits

Abstract Traditional arc welding was applied to create Fe-based hardfacing deposits onto carbon steel substrates used on the edges of excavation equipment in a quarry plant, in order to enhance their service lifetime. Three electrodes of different chemical composition were used to deposit 5–6 mm-thick protective overlayers. Prior to laboratory characterisation of the surface-hardened samples, the Thermocalc© software was used to predict microstructure features that could be possibly present in the weld metal areas after solidification, taking into account a 10% dissolution of the base metal in the molten pool. The calculation results were compared to the experimental findings from optical and scanning electron microscopy observations, X-ray diffraction and microhardness measurements. The thermodynamic calculations provided an accurate prediction of the phases obtained, whilst microhardness values and their distribution were found to be strongly depended on the nature of the carbides, their interaction with the liquid metallic matrix and their dispersion within the final solid.