Microstructure and Abrasive Wear Behavior of Fe–Cr–C Hardfacing on Hammer Tips for Sugarcane Shredders

This study investigates the influence of an austenitic buffer layer on the microstructure, hardness, and abrasive wear resistance of Fe–Cr–C hardfacing applied to high-chromium white cast iron (HCWCI) hammer tips used in sugarcane shredders. Hardfacing was performed by shielded metal arc welding with two Fe–Cr–C layers deposited directly on the HCWCI substrate and with an austenitic buffer layer followed by an Fe–Cr–C hardfacing layer. Microstructural characterization was carried out using optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, while hardness profiles were determined by micro-Vickers testing. Abrasive wear behavior was evaluated using a dry sand–rubber wheel test according to ASTM G65. The non-buffered hardfacing layer exhibited a hypereutectic Fe–Cr–C microstructure consisting of coarse primary chromium carbides, resulting in high hardness values of approximately 840 HV. In contrast, the buffered sample showed an austenite-rich matrix with finer eutectic carbides and reduced hardness of around 600 HV. Abrasive wear tests of the non-buffered sample showed a lower mass loss, whereas the buffered sample exhibited a substantially higher mass loss. These results demonstrate that Fe–Cr–C hardfacing without a buffer layer provides superior wear resistance.