Effect of Ti and Nb on microstructure and properties of Fe based surfacing alloy

Fe-Cr-C-B Fe based surfacing alloy was prepared by changing the addition of Ti or Nb. The microstructure and properties of surfacing alloy were tested and analyzed by means of scanning electron microscope, X-ray diffraction, Rockwell hardness tester and wear tester. The results show that in the surfacing alloy containing Ti or Nb, the primary austenite grain is refined, the eutectic structure is evenly distributed in a broken network, and black circular or massive TiC and rhombic or triangular NbC hard phase particles are formed respectively. The microstructure of the surfacing alloy with 5% Ti is the smallest. Tic or NbC hard phase particles are evenly dispersed in the structure and can be used as wear-resistant particles to form a wear-resistant skeleton with refined primary austenite and eutectic structure to jointly resist the wedging and cutting effect of wear particles. When the content of Ti is 5%, the surfacing alloy containing Ti achieves the best wear resistance, the hardness is 66 HRC and the wear amount is 0.048 7 g; When the addition of Nb is 4%, the surfacing alloy containing Nb achieves the best wear resistance, the hardness is 65 HRC and the wear amount is 0.052 4 g. Under the same conditions, the iron-based surfacing alloy containing an appropriate amount of Ti has better wear resistance.