| Rotary blade works long-term to withstand the frequently impact and wear of stone,straw,weed,etc.in the soil,which is easy to fail due to wear.The frequent failure of rotary blade not only seriously affects the working efficiency and working quality of the implements,but frequently changing the rotary blade will increase the cost of the operating even delay the farming.In order to improve the wear resistance of the rotary blade,the essay puts the Fe-Cr-C-V alloy powder as surfacing material and uses plasma surfacing technology to prepare Fe-Cr-C-V surfacing layer,which is used to study the microstructure and mechanical properties of the Fe-Cr-C-V surfacing layer,the main contents are as follows:Fe-Cr-C-V surfacing layer was prepared on the surface of 65Mn steel by plasma surfacing technology with FJ-19 and FeV80 as surfacing material.Taking the wear loss of the surfacing layer as the evaluation index,the ratio of FJ-19 and FeV80 was optimized by single factor experiment,and the optimal ratio of FJ-19 and FeV80 was determined to be7:1（V element mass fraction was 10%）:taking the wear loss of the surfacing layer as an evaluation index,the orthogonal test was used to analyze the significance level of the influence of surfacing parameters on the wear loss（surfacing current>surfacing distance>surfacing speed>powder feeding rate）,and optimize the parameters of the plasma surfacing technology（surfacing current 55 A,surfacing distance 5 mm,surfacing speed 16cm/min,powder feeding rate 15 g/min）.FJ-19 surfacing layer and Fe-Cr-C-V surfacing layer were prepared by the plasma surfacing machine with optimized surfacing parameters.The microstructure and phase of the surfacing layer were analyzed by metallographic microscope,scanning electron microscope,EDS spectrometer and X-ray diffraction.The result shows that the content of M7C3 and Fe-Cr solid solution in the Fe-Cr-C-V surfacing layer were increased and the VC phase is formed in situ compared with FJ-19 surfacing layer;the grain size of Fe-Cr-C-V surfacing layer is fine and dispersed.The hardness,friction coefficient,wear loss and impact toughness of ordinary heat treated（840℃quenching,400℃tempering）65Mn steel,FJ-19 surfacing layer and Fe-Cr-C-V surfacing layer were compared and analyzed by Vickers hardness tester,reciprocating friction and abrasion tester and impact tester.The result shows that the average Vickers hardness of Fe-Cr-C-V surfacing layer is as high as HV0.5810（65Mn steel is HV0.5460,FJ-19 surfacing layer is HV0.5710）;the friction coefficient of Fe-Cr-C-V surfacing layer is only 0.52（65Mn steel is 0.75,FJ-19 surfacing layer is 0.55）;compared with 65Mn steel,the wear loss of Fe-Cr-C-V surfacing layer is reduced by 2/3;compared with FJ-19 surfacing layer,the wear loss of Fe-Cr-C-V surfacing layer is reduced by 11%and the impact toughness is increased by 21%（FJ-19 surfacing layer is 6.2 J/cm2,Fe-Cr-C-V surfacing layer is 7.5 J/cm2）.A field-comparison test was carried out on rotary blades with a Fe-Cr-C-V surfacing layer and commercially available 65Mn rotary blades,which was operating on an area of23.3 hm2.The result shows that the 65Mn rotary blade has obvious wear marks,the blade passivation is serious,and the average wear loss is 60 g.The surface of the rotary blade strengthened by Fe-Cr-C-V surfacing layer is smooth and clean,no serious wear marks and surfacing layer fall off,and the average wear loss is only 32 g. |
