摘要
采用金属粉型药芯焊丝自保护明弧堆焊方法制备了Fe-C-Cr-Nb-B系堆焊合金。采用光学显微镜、X射线衍射仪、显微硬度计、扫描电镜以及电子能谱仪,研究了铌铁含量对其显微组织和耐磨性的影响。结果表明,随着外加铌铁含量增加,该明弧堆焊合金的显微组织由共晶结构转变成含先析出NbC相的亚共晶结构,宏观硬度从64 HRC增加至69 HRC;NbC相分别呈点状、条状、块状、树枝状等,尺寸可达5～25μm,远大于晶内析出相,且其显微硬度逐渐增加,最高可至2290 HV0.1。耐磨性试验和磨损表面形貌分析结果表明,先期析出一定数量的NbC颗粒显著改善了Fe-C-Cr-Nb-B系明弧堆焊合金的耐磨性,其耐磨性与NbC颗粒尺寸、致密度和数量有关,其中尺寸效应尤其显著。
Fe-C-Cr-Nb-B hardfacing alloys were deposited by flux-cored wire self-shielded open arc welding. The effects of Fe-Nb content in the core of the wire on the microstructnre of hardfacing alloys were investigated by optical microscopy （OM）, X-ray diffractometer （XRD）, micro-hardness tester, scanning electron microscopy （SEM） together with energy dispersive spectrometer （EDS）. The results show that with the increasing addition of Fe-Nb powders, the microstructure of the deposited alloys changes from an eutectic texture into a hypereutectic one following by the precipitation of primary NbC phases. The bulk hardness increases from 64HRC to 69HRC. For those NbC grains, the shape of dot-like, strip-like, block-like and tree-like is respectively observed and their size is 5-25 μm, which is far higher than those precipitated from the intra-crystalline. The microhardness of NbC grains gradually rises up to 2290HV0.1. The results of abrasion test and the analysis of worn morphology indicate that a quantity of pro-precipitated NbC grains significantly improve the abrasion resistance of Fe-C-Cr-Nb-B system open arc hardfacing alloys and their abrasion resistance is determined by the size, the tightness and the volume fraction of NbC phases, especially the size.
出处
《热加工工艺》
CSCD
北大核心
2013年第19期21-25,共5页
Hot Working Technology
基金
湖南省自然科学基金委员会和湘潭市政府自然科学联合基金项目(11JJ9015)
国家自然科学基金面上项目(51271158)
关键词
明弧
堆焊
耐磨性
NBC
显微组织
open arc
hardfacing
wear resistance
NbC
microstructure
