Ti和Nb对铁基堆焊合金组织性能的影响

改变Ti或Nb的添加量制备Fe-Cr-C-B系铁基堆焊合金.借助扫描电镜、X射线衍射仪、洛氏硬度计和磨损试验机对堆焊合金组织性能进行测试分析.结果表明，在含Ti或Nb的堆焊合金中，初生奥氏体晶粒细化，共晶组织呈断网状均匀分布，并分别有黑色圆形或块状TiC和菱形或三角形NbC硬质相颗粒生成，添加5%Ti的堆焊合金组织最细小.TiC或NbC硬质相颗粒在组织中呈均匀弥散分布，能够作为耐磨质点与细化的初生奥氏体和共晶组织构成耐磨骨架，共同抵抗磨粒的楔入与切削作用.当Ti添加量为5%时，含Ti堆焊合金达到最优耐磨性，硬度为66 HRC，磨损量为0.048 7 g；当Nb添加量为4%时，含Nb堆焊合金达到最优耐磨性，硬度为65 HRC，磨损量为0.052 4 g.在同等条件下，含有适量Ti的铁基堆焊合金具有更优的耐磨性.

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.