等离子原位合成Fe-Cr-V-C堆焊合金的耐磨性

Wear Resistance of In-situ Fe-Cr-V-C Hardfacing Alloys Fabricated by Plasma Transferred Arc Weld-surfacing Process

采用等离子堆焊技术制备了不同Cr含量的Fe-Cr-V-C堆焊合金,借助扫描电镜和X射线衍射等分析手段研究了碳化物形貌及合金物相组成。同时研究了Cr含量对合金硬度和耐磨性的影响,并探讨了磨损机理。结果表明:堆焊合金组织由马氏体、铁素体、奥氏体、M7C3及VC组成。合金中随着Cr含量的提高,由于硬质相M7C3和VC的数量及形态变化不大,而具有高硬度的针状马氏体基体组织的减少使得合金的耐磨性先降低,当达到一定值后继续增加Cr含量,M7C3的数量逐渐增多,因而耐磨性随后增大;当Cr含量达到27.2%(质量分数)时,大量高硬度六边形M7C3复合物(约HV1200)结合一定量VC(约HV1600)颗粒构成坚实的耐磨骨架,使得合金具有最佳的耐磨性。

Fe-Cr-V-C hardfacing alloys with different Cr contents were prepared under plasma trans- ferred arc （PTA）. The phases constitution, carbide morphology were investigated by means of scanning electron microscopy（SEM） and X-ray diffraction（XRD）. The effect of Cr contents on the wear resistance of hardfacing alloys was detected by using Rockwell hardometer and wear testing machine. In addition, the abrasion wear mechanism was discussed. The results show that the microstructure consists of martensite, ferrite and austenite, carbides such as primary M7C3, VC. As the Cr contents increase, the wear resistance first decreases because of the little changes of content and morphology for M7 C3 and VC hard phases and the decrease of acicular martensite with high hardness, afterwards, the wear resistance increases when Cr content reaches a particular value as a result of the increase of M7C3 contents. When Cr mass fraction is 27.2%, a high volume fraction of hexagonal （Fe,Cr,V）TC~ complex carbides and a small amount globular VC particles in the microstructure form a substantial wear resistant structure, which leads to an excellent wear resistance.