Effect of B Content on Microstructure and Wear Resistance of Fe-Cr-C Surfacing Alloy

In order to further improve the wear resistance of Fe-Cr-C surfacing alloy, Fe-Cr-C wear-resistant surfacing alloy layers with different B addition amounts were prepared on the surface of Q235 steel by adjusting the amount of ferroboron powder added to the surfacing alloy powder using plasma powder surfacing technology.The effects of B addition amount on the microstructure, phase composition and wear resistance of Fe-Cr-C surfacing alloy were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), abrasive wear tests and other analysis and testing methods.Results showed that when the addition amount of B was 0, the microstructure of the surfacing alloy was composed of dendritic Fe and chrysanthemum-like (Fe, Cr)7(C, B)3＋Fe eutectic structure.With the increase of B addition amount, the volume fraction of the (Fe, Cr)7(C, B)3 hard phase in the surfacing layer increased.After the precipitation amount of the (Fe, Cr)7(C, B)3 phase reached a certain value, the primary B0.7Fe3C0.3 phase was formed.When the B addition amount was 20.0%(mass fraction), a large amount of the (Fe, Cr)2 B hard phase was precipitated.The hardness of the surfacing layer showed an overall trend of rising-steep drop-rising, and the hardness of the B-10 sample reached 63.1 HRC.The results of the abrasive wear test showed that the wear resistance of the surfacing alloy layer exhibited an trend of upward-flat- upward, and the wear resistance of the B-20 sample increased to 2.8 times that of the B-0 sample.