Study On Laser Cladding Ni Based Alloy Coating And Wear Behavior Of Wheel Rail Material

High speed is an important direction of the railway development in our country for the future,which can lead to the aggravation of wheel and rail easily and affect the rapid development of railway.Laser cladding as a kind of advanced surface treatment technology that through the high energy laser beam cladding material,rapid solidification,rapid melting and cladding material,good metallurgical bonding with the substrate,which can improve the hardness,strength,wear resistance significantly.In this paper,ER8 wheel steel and rail steel as matrix materials and the cladding material is Ni60 based alloy powder that are added 4% Mo,1% Y₂O₃,5% ZrO₂ that get four kinds of Ni60 based cladding materials as the research object.Laser cladding of 4 pairs of wheel and rail specimens was carried out by laser cladding equipment,get four kinds of Ni60 based alloy wheel rail specimen the cladding layer,and study organization structure hardness and wear resistance of the four kinds of cladding layer.According to the analysis of the experimental results,which found that the cladding layer is composed of three parts mainly: the cladding zone,the bonding zone and the heat affected zone.The microstructure of the cladding layer is mainly composed of dendrite,granular and rod like crystal structure,coarse dendrite,and crystal structure.The analysis of measuring hardness,surface hardness of wheel and rail and found that the surface hardness of wheel and rail has been improved about twice,and the hardness of the cladding area is the highest,while the matrix hardness is the lowest,the hardness difference reason that solid solution strengthening,grain refinement and carbides in cladding layer.Analysis on wear and friction coefficient,found the laser cladding wear ratio is obious less than without the laser cladding treatment,and the friction coefficient of laser cladding is less than without the laser cladding,the reason that the hardness,strength toughness and the wear resistance of the laser cladding of specimens has been improved.