VC对铁基合金喷焊层组织与耐磨性影响

Effect of addition of VC on microstructure and wear resistance of Fe-based alloy coatings by plasma transferred arc welding

采用等离子喷焊技术在Q235钢表面制备了铁基合金涂层,采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)以及销盘磨损实验,研究了VC加入量对铁基合金喷焊层组织和耐磨性能的影响。结果表明:未加VC的铁基合金喷焊层主要由α-Fe,γ-Fe和(Cr,Fe)7C3组成;加入2.0%VC时,γ-Fe相消失;当VC的加入量达10%时,γ-Fe相又出现,且出现了VC相;VC作为异质形核基底,促进了形核,细化晶粒,并改变了共晶组织形貌,提高了喷焊层的硬度和耐磨性能。未加VC时,喷焊层的耐磨机理主要为疲劳剥落,加入VC以后,喷焊层的疲劳剥落逐渐减弱并出现犁沟。

Fe-based alloy coatings with and without VC particles on Q235 steel substrate were prepared by plasma transferred arc welding.Microstructure and tribological characteristics of the coatings were investigated by optical microscope,scanning electron microscopy,X-ray diffraction and wear tests. The results show that there are α-Fe,γ-Fe and（ Cr,Fe）7C3exist in the coatings without VC addition. The γ-Fe phase disappears by adding 2. 0% VC,which reappears and VC phase is identified in the coating with the addition of 10. 0% VC. The restrained growth of the dendrites and improved eutectic microstructure are observed in the coatings because VC particles acted as heterogeneous nucleation substrate to promote the nucleation and refine the grains. The microhardness and wear resistance of the coatings are greatly improved with the VC addition. The predominant wear mechanism of the coatings changes from spalling fatigue to appearing of plowing grooves by adding VC.