Abstract: In order to study the evolution of the microstructure and properties of Fe-Cr-Mn-Ni alloy deposited metal under B/N composite strengthening, flux cored wires with different nitrogen contents were coated on the surface of carbon steel by gas metal-arc welding(GMAW). The hardness and wear resistance of the deposited metal were tested, the wear morphology and the microstructure of the surfacing metal were characterized by SEM and XRD, and the evolution of the microstructure and properties of nitrogen-containing flux cored wire were analyzed. The results show that the deposited metal consists of matrix γ and precipitates M2B, BN, Cr(C, N), and the shape of precipitates are grid and fishbone. The addition of N element can promote the precipitation of nitride and boride, and make them disperse and improve the comprehensive mechanical properties of the surfacing metal. When the content of N increases to 1.0%, the mechanical properties of the deposited metal are the best. At this time, the hardness is 44 HRC, the wear amount is 0.0139 g, and the friction coefficient is0.33. With the increase of N content, the wear mechanism of the surfacing metal changes from abrasive wear to adhesive wear.With the increase of wear temperature, the wear resistance of cladding layer decreases, and the wear mechanism changes from adhesive wear to abrasive wear.