钻杆接头耐磨带堆焊药芯焊丝的研究

摘要

A kind of flux cored wire was developed to deposited the wear resistant band on drill pipe. The deposited alloys of Fe-B-Nb-Ni were prepared by CO2 gas shielded flux cored arc welding. The microstructures of the Fe-B-Nb-Ni alloys were investigated by optical microscopy, scanning electron microscopy,X-ray diffraction,etc. At the same times,its hardness and the wear resistance of the surfacing layer were tested. The results show that the Fe-B-Nb-Ni alloy exhibits, excellent wear resistance which is higher 37% than the imported flux-cored wire. The hardness value of the Fe-B-Nb-Ni alloy is up to HRC60. 5 ~ 62. 2. The microstructure of the Fe-B-Nb-Ni alloy consists of ferrite + martensite + Fe3C + NbC + eutectic structure Fe3 ( B,C) + Fe23 (B,C)6 + Fe2B. A large number of fine niobium carbides are randomly dispersed in the microstructure of the alloys. The martensite as wear skeleton shows well strength and wear resistance. The wear mechanism of Fe-B-Nb-Ni abrasive wear resistant layer was mainly plough and brittle peeling.%研制一种Fe-B-Nb-Ni系钻杆耐磨带堆焊药芯焊丝,采用CO2气体保护堆焊方法,制备Fe-B-Nb-Ni耐磨堆焊合金,利用OM,SEM,XRD等方法对堆焊合金的显微组织进行了观察分析,对堆焊层的硬度及耐磨性能进行了测试分析.结果表明,Fe-B-Nb-Ni堆焊合金耐磨性能比国外某进口药芯焊丝提高了约37％,其宏观硬度值达到HRC60.5～62.2.Fe-B-Nb-Ni堆焊合金的显微组织为马氏体+铁素体+少量渗碳体+颗粒状NbC+包晶Fe3(B,C)+共晶Fe23(B,C)6、Fe3(B,C)+少量共晶Fe2B相,其中NbC硬质颗粒弥散的分布于基体中,基体中的马氏体组织具有优异的强度和耐磨性,起到了很好的耐磨骨架的作用.Fe-B-Nb-Ni堆焊合金的磨损机理主要是犁沟式微切削和局部的硬质相剥落.