Process And Abrasive Wear Performance Research On Plasma Iron-based Wear-resistant Coating

In the course of field work,the rotary blade is subjected to the frequent friction and impact of sand,stones and weeds in the soil.The wear failure and service life of rotary blade affect the quality of rotary tillage,In order to improve the wear resistance and prolong the service life of the rotary blade,In this paper,an automatic plasma cladding platform has been designed and assemble,using Fe5 iron base alloy powder as cladding material,Fe5 cladding layer was prepared on 65Mn spring steel and 45 steel for rotary blade,the microstructure and properties of the cladding layer were characterized and analyzed.Fe5 wear-resistant coating was clad on the cutting edge of rotary blade,and its wear performance was evaluated by soil groove wear test.The main contents are as follows:Designing and assemble automatic plasma cladding platform,mainly including plasma cladding machine（including plasma cladding power supply,gas and powder supply system,etc.）,three-axis mobile platform and positioner,the effective stroke of the X,Y and Z axis modules of the self-designed three-axis mobile platform is 1000mm,1000mm and 300mm,respectively,the horizontal velocity of the three axis modules is 320mm/s,the vertical velocity is 200mm/s,and the moving precision is 0.5mm,the three-axis mobile platform can run the automatic control program quickly and stably,and improve the efficiency and quality of plasma cladding effectively.The preparation process of Fe5 plasma cladding layer was optimized by single factor test and orthogonal test.With average vickers hardness as the evaluation index,the effects of cladding current,cladding speed and powder feeding rate on the plasma cladding layer were systematically studied.With the wear loss weight as the evaluation index,the influence of the cladding parameters on the cladding quality is analyzed as cladding current≈cladding speed>powder feeding rate.The optimum cladding current,cladding speed and powder feeding rate of plasma cladding Fe5 powder are determined by two kinds of experiments,which are 140A,25mm/s and 25g/min.The microstructure and phase structure of Fe5 plasma cladding layer were analyzed by metallographic microscope and XRD.The results show that the average thickness of the cladding zone is about 1500μm,and the microstructure of the cladding layer is mostly hexagonal,needle-shaped and quadrilateral,which shows dispersion distribution,the main hard phase are Cr₇C₃and Cr₂₃C₆.The hardness and abrasive wear properties of Fe5 plasma cladding layer were measured and analyzed by microhardness Tester and green sand rubber wheel tester.The results show that the average Vickers hardness of Fe5 cladding layer based on 45 steel and 65Mn steel is HV_0.5952.1 and HV_0.5948.9,and the average hardness of 65Mn steel is HV_0.5456,45 steel is only HV_0.5163.7.Compared with 65Mn steel,the wear weight loss of Fe5 plasma cladding layer is only 1/15 of 65Mn steel.Plasma cladding Fe5 wear-resistant coating on the cutting edge of rotary blade was used to analyze its microhardness and compare test of soil trough.The results show that the hardness and quality of Fe5 cladding layer on rotary blade are similar to those of Fe5cladding layer on 65Mn steel substrate,the grinding loss of Fe5 plasma cladding coating rotary blade is 1/3 of non-cladding coating rotary blade.