Study On Wear Resistance And Corrosion Resistance Of Turn Plough By Laser Cladding Coating On The Surface

The wear and corrosion failure of plough bracket will be caused by the soil during tillage,which will affect plough bracket's tillage efficiency and service life.The alloy coating prepared by laser cladding technology has good mechanical properties,and can be used to improve the wear and corrosion resistance of plough bracket materials and the service life of plough bracket.The quality,hardness and phase structure of Fe-based alloy coatings with different composition were analyzed.The wear and corrosion resistance of the coatings and65Mn steel were compared,and the wear and corrosion mechanism of the materials with different grain size and salinity of gravel was studied.In this paper,ANSYS software is used to simulate and analyze the temperature distribution on the material surface during laser cladding.The simulation results show that with the increase of laser cladding power,the central temperature of laser spot on the coating surface and the maximum temperature on the substrate surface also increase,and the temperature variation law accords with the characteristics of rapid heating and cooling of laser cladding.In the direction of specimen height,the farther away from the cladding surface,the temperature gradually decreases.When the laser power is 800w,the surface temperature of the cladding coating is 3570K,which reaches the powder melting point;the surface temperature of the matrix is 1865K;the melting point of the 65Mn steel matrix is reached,which can realize the melting of the cladding powder and the metallurgical bonding between the cladding layer and the matrix.Through the analysis of the surface quality of nine groups of different powder cladding,it is found that the surface is smoother with the increase of chromium and nickel content.The analysis of orthogonal experiment shows that the C content of the three elements has the greatest influence on the hardness of the cladding layer,followed by the content of Cr and Ni.The optimum ratio of the nine groups is 2%C content,25%Cr content and 8%Ni content.The surface quality of group 9 cladding coatings is the best and the hardness is 61HRC.Through XRD analysis of the cladding coating,the cladding coating mainly contains intermetallic compounds such as Cr₂₃C₆,M₃C,Cr₂C₃ and Ni₃Fe.The structure of the cladding coating is mainly?acicular?lath martensite and serrated wei-ferrite,and the coarse dendrite is mainly on the solid-liquid interface at the bottom of the molten pool.Cellular crystals are dominant in the upper part of the cladding layer.The wear tests show that the impact/erosion abrasive wear increases with the increase of wear time,and there is a size effect.In the same time,with the increase of gravel size,the wear rate increases slowly to sharply.In the same time,impact abrasive wear causes greater mass loss than erosion abrasive wear.The impact abrasive wear surface is mainly impact pit,and the erosion abrasive wear surface is mainly plough groove scratch.Compared with 65Mn steel cladding coating,it has better wear resistance due to the increase of hardness.The corrosion test results show that the corrosion rate of materials in two kinds of corrosive soils is constant,and the conductivity of soil solution increases with the increase of soil salinity,which accelerates the corrosion of materials.The corrosion first occurs in the contact area between soil and material surface.With the increase of time,the corrosion area of65Mn steel extends from point corrosion to total corrosion;the corrosion of cladding coating occurs in the absence of corrosion.The pitted edge area is pitted selective corrosion,and the corrosion products of the two materials are mainly iron oxide.In both soil environments,the coating has better corrosion resistance than 65Mn steel due to the existence of passive film.