Study On Composite Reinforced Wear Resistant Surfacing Flux Cored Wire

The rapid development of industry has made a higher requirements for wear-resistant materials.On the surface of the parts,a layer of high wear resistance metal layer can effectively improve the service life.This paper is based on the traditional Fe-Cr-C alloy system.We prepared multiple composite reinforced wear-resistant hardfacing flux-cored wire with Fe-Cr-C-B,Fe-Cr-C-B-Nb,Fe-Cr-C-B-Ti three kinds of alloy system.The surfacing layers were prepared by self-shielded arc welding method.The types and distribution patterns of hard phases in the surfacing layer were discussed.The influence of the change of element content on the hardness and wear resistance of the surfacing layer was analyzed.The content of Cr was optimized in Fe-Cr-C-B surfacing alloy.And the influence of boron addition on the microstructure and wear resistance of surfacing layer was studied.With the addition of boron,the microstructure changes from M23C6 into M₂₃?C,B?₆.For those dispersed borides,the shape of lamellar-like,chrysanthemum-like is respectively observed.The results of abrasion test indicate that a quantity of borides improve the abrasion resistance of Fe-Cr-C-B hardfacing alloys and their abrasion resistance is determined by the number,the tightness and the size of borides.In the Fe-Cr-C-B-Nb surfacing alloy,the microstructure is Martensite,retained austenite,M₂₃?C,B?₆,and NbC.Boride M₂₃?C,B?₆ is distributed along the grain boundaries while the regular quadrilateral shape of NbC is distributed in martensite.NbC before M₂₃?C,B?₆ generation.The excess B is not conducive to the precipitation of NbC,Nb and the solid solution strengthening of boride and matrix The results of abrasion test indicate that M₂₃?C,B?₆ and NbC significantly improve the abrasion resistance of Fe-Cr-C-B-Nb hardfacing alloys.In the Fe-Cr-C-B-Ti surfacing alloy,TiC and M₂₃?C,B?₆ are synthesized in situ.With the increase of Ti content,the number of TiC in the microstructure gradually increased and distributed along the grain boundary.The increase of boron content makes the quantity of TiC unstable.TiC as a nucleation substrate,provide the conditions for M₂₃?C,B?₆ epiphytic growth.In-situ synthesis of TiC and M₂₃?C,B?₆ hard phases can improve the comprehensive properties of the surfacing layer.