Development of slag-free self-shielded flux cored wire with niobium addition for hardfacing

Fe-Cr-Nb-C series self-shielded flux-cored wires were developed.The wire exhibits excellent processing performances when it contains 12% Mn-Fe, 6% Si-Fe, 8% graphite and 4% Ti-Fe.The microstructure of the deposited metal is nearly austenite, a small quantity of martensite, primary carbide and eutectic crystal, the hardness changes from 40 HRC to 50 HRC with different niobium contents.When the carbon content is limited, niobium carbide is formed in the welding process, which not only improves the quantity of carbides, but also influences the formation of chromium carbide.