Tribological performance under abrasive wear of Fe-Cr-C plus Nb coating deposited by FCAW process

This paper aims to investigate the abrasion resistance performance of Iron-Crhomium-Carbon + Niobium (Fe-Cr -C + Nb) coatings deposited by Flux-Cored Arc Welding (FCAW) process. Two coatings conditions were prepared in a 1-layer setup, with a selfshielded tubular wire over SAE 1020 carbon steel substrate, varying the FCAW parameterization levels, searching to reproduce different conditions of welding energy and their respective ef-fects on the coatings' properties. Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) were employed in the microstructure and wear micromechanism analysis. X-ray Energy Dispersive Spectroscopy (EDS) was used for chemical composition assessment and Vickers microdurometer for hardness evaluation. In the tribological attempt, it was used the dry/sand rubber wheel apparatus according to ASTM G65. From the results, in neither sample of the two coating conditions, deleterious defects were observed on the surfaces, as well as in the cross-sections, such as lack of fusion and process interruptions. Dilutions were sufficient to ensure metal-lurgical bond without compromising layer geometry. Cold cracking characteristics of the process and material were observed, which did not significantly influence the performance of the coatings. The microstructure of both coatings showed CrC and NbC carbides dispersed in the Fe-matrix, whose volume fraction and mean free path between them varied as a function of dilution. The greater Nb-content and less intense heat input in the lower dilution coating provided greater refining of the CrC, NbC, and Fe-matrix strength, which was reflected in higher hardness, lower wear rate, and less severe abrasive wear micromechanism.

Automated summary

This study investigates the abrasion resistance performance of Fe-Cr -C + Nb coatings deposited by FCAW process. The effects of different welding energy conditions on the coatings' properties were analyzed using OM, SEM, EDS, and Vickers microdurometer. Dry/sand rubber wheel apparatus was used for the tribological attempt. The microstructure of the coatings showed dispersed carbides in the Fe-matrix, and the hardness, wear rate, and abrasive wear micromechanism varied with dilution.