Microstructure And Property Control Of Tungsten And Boron Multiple-component Hard Phases Reinforced Hardfacing Alloy

As the main form of mechanical failure,wear will reduce the service life of mechanical equipment and increase the risk of accidents in mechanical engineering,so it is necessary to improve the wear resistance of material surface.In this paper,the Fe-Cr-C-B-W system hardfacing alloy was prepared by submerged arc welding machine with bright arc surfacing.By changing the content of Cr,W and B elements in flux cored wire,to explore the influence of three elements on hard phases,hardness and wear resistance in surfacing welding layer,to explore the wear mechanism of surfacing welding layer.Determine the optimal alloy element content of Fe-Cr-C-B-W surfacing alloy to achieve the best wear resistance of surfacing welding layer,and developed a self-protective wear-resistant surfacing flux-cored wire with excellent performance.When the Cr element is added in an amount of 15%to 35%,the weld shape is good,and the arc is stable during the welding process.When the W is added in an amount of 22%,there will produce more fume,splash and there will be arc breaking during the welding process.When the B is added in an amount of 6%to 8%,boron iron in flux cored wire can enhance the fluidity of deposited metal and promote the formation of weld.When the B is added in an amount of 12%,slag inclusion will occur during the welding process.According to the analysis of XRD,SEM and EDS,when the content of Cr element in the surfacing welding layer metal is 12.16%,the main chromium-containing hard phases in surfacing welding layer are?Cr,Fe?₇C₃,Cr₇C₃ and Cr₂₃C₆.When the content of W in the surfacing welding layer is 6.22%,the tungsten-containing hard phases in surfacing welding layer are FeWB,FeW₃C,W₂C.When the content of B in the surfacing welding layer is1.96%,the resulting boron-containing hard phases are FeWB,Fe₂₃?C,B?₆,CrB,Cr₂B.By observing the metallographic appearance and scanning morphology of the surfacing welding layer,it is determined that increasing the content of Cr,W and B can reduce the austenite grain and increase the eutectic structure.Cr and W are ferrite forming elements,which can shrink the austenite phase region and increase the ferrite phase region.Through hardness test and wear resistance test,it is proved that under the condition of changing one of Cr,W and B elements,when the content of Cr in the surfacing welding layer metal is 12.16%,the wear resistance of the surfacing welding layer is the best.When the W element content is 5.36%,the wear resistance of the surfacing welding layer is the best.And when the B element content is 1.96%,the wear resistance of the surfacing welding layer is the best.When the content of W element in the surfacing welding layer is metal6.22%,the hardenability of the surfacing welding layer increases.The hard phase is easy to fall in the process of wear,resulting in a slight decrease in wear resistance.When the content of B element in the surfacing welding layer is 2.28%,part of B element is distributed in the grain boundary,which leads to the embrittlement of the surfacing welding layer.Although the hardness of the surfacing welding layer metal increases,the wear resistance of the surfacing welding layer metal decreases.Through the L₉?3⁴?orthogonal experiment,it was confirmed that the effects of Cr,W,and B elements on the wear resistance of the surfacing welding layer in descending order are Cr,W,and B.And the best element content of Fe-Cr-C-B-W surfacing welding layer metal is C1.52%,Cr11.57%,W4.88%,B1.87%.At this time,the wear value of the surfacing welding layer is 0.2847g,and the wear resistance of the surfacing welding layer is the best.