Ti和Nb对铁基堆焊合金组织性能的影响

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

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.

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 evenlydispersed in the structure and can be used as wear-resistantparticles to form a wear-resistant skeleton with refined primaryaustenite and eutectic structure to jointly resist the wedging andcutting 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 7g;When the addition of Nb is 4%, the surfacing alloy containingNb achieves the best wear resistance, the hardness is 65HRC and the wear amount is 0.052 4 g. Under the same conditions,the iron-based surfacing alloy containing an appropriateamount of Ti has better wear resistance.