Microstructure and abrasive wear property of Fe-Cr-Nb-B-C alloy deposited by laser cladding with metal powder cored wire

Objective The aim is to investigate the phase composition, microstructure and abrasive wear property of Fe-Cr-Nb-B-C metal powder core wire laser cladding layer. Methods Fe-Cr-Nb-B-C metal powder cored wire with diameter of 1.2 mm is prepared and iron-based cladding layers with different B contents are then deposited on 316L stainless steel substrates using laser wire feeding cladding techniques. The phase composition of the cladding layer is analyzed by optical microscope (OM), hardness tester, scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and an MLS-225 wet rubber wheel abrasive wear tester. The phase composition, microstructure, microhardness, Rockwell hardness and abrasive wear property of the cladding layer are investigated. Results The results show that the wear-resistant cladding layer primarily consisted of γ-Fe, NbC, M₂₃(C,B)₆ and a small amount of α-Fe, with the NbC hard phases forming preferentially. During laser wire cladding, when the Nb element content of the cladding layer is about 5.7% and the B element content is 0.9%, the addition of boron carbide led to optimal cladding layer property, characterized by high hardness and superior wear resistance. Conclusion As the B element content increases, the abrasive wear resistance of Fe-Cr-Nb-B-C alloy cladding layers improved significantly. The in-situ generated NbC and M₂₃(C,B)₆ hard phases within the cladding layer is identified as the primary reasons for the enhanced hardness and wear resistance.