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采用药芯焊丝自保护明弧焊方法制备了Cr8B4C2Ti Si高硼堆焊合金,借助光学显微镜、X射线衍射仪、扫描电镜以及电子能谱仪,考察了Ti含量对其显微组织及耐磨性的影响。结果表明:该高硼堆焊合金中M_(23)(C,B)6相先于M3(C,B)相形成,显著抑制了γ-Fe+Fe_3(C,B)脆性共晶相的形成而改善了其韧性和耐磨性;随着Ti加入,先期析出Ti_8C_5颗粒充当初生M_2B的非均匀形核核心,促使其尺寸减小且弥散分布,也使包裹该相的M_(23)(C,B)6逐渐减少,改变为共晶M_(23)(C,B)_6;过多的Ti_8C_5相析出会耗尽熔体中过多的碳,致使初生M_2B相生长阻力减小而择优长大为板条状晶,且Ti_8C_5相吸碳生长而使M2B相胀裂。Cr8B4C2TiSi高硼堆焊合金的宏观硬度和磨损量随着钛含量增加首先轻微波动,当增至1.2%时,耐磨性最好,其磨损机理包含微观剥落和微切削两种,微观剥落为其主要磨损机制。
Cr8B4C2Ti Si high boron surfacing alloy was prepared by self-shielded arc welding with flux-cored wire. The microstructure and wear resistance of Ti were examined by optical microscope, X-ray diffraction, scanning electron microscopy and electron spectroscopy. Impact. The results show that the M_ (23) (C, B) 6 phase in the high boron surfacing alloy is formed before the M3 (C, B) phase and the brittle eutectic phase of γ-Fe + Fe_3 Forming and improving its toughness and wear resistance; With the addition of Ti, precipitated Ti_8C_5 particles as the primary non-uniform nucleation of M_2B core, to promote its size and dispersion, but also to wrap the phase M_ (23) ( C, B) 6 to eutectic M_ (23) (C, B) _6. Excessive Ti_8C_5 phase precipitation will deplete too much carbon in the melt, leading to a decrease in the growth resistance of primary M_2B phase. Grow into lath crystal, and Ti_8C_5 phase carbon absorption growth M2B phase split. The microhardness and wear of Cr8B4C2TiSi high boron surfacing alloy first fluctuate slightly with the increase of titanium content. When the content increases to 1.2%, the wear resistance is the best, the wear mechanism includes two kinds of micro-peeling and micro-cutting, the micro-peeling is The main wear mechanism.