Numerical Simulation Of Laser Cladding Ni/WC Coating And Study On Microstructure And Properties Of Coating

High manganese steel exhibits excellent wear resistance under strong impact,and is thus commonly used in mines,metallurgy,railways,electric power and other industries,but only in the case of large impact,high stress,abrasive hard,high manganese steel The high wear resistance has been reflected.As an application of laser cladding surface hardening technology is very broad is an effective means to improve its wear resistance.Therefore,in this paper,the surface of high manganese steel clad with a layer of Ni / WC composite coating by laser cladding surface modification technology,in order to improve the wear resistance of high manganese steel,and do laser cladding numerical simulation,hope by combining Experimental results and simulation results were analyzed to study the microstructure and properties of the cladding.The main research contents are as follows:(1)According to the characteristics of co-axial laser cladding,the finite element software ANSYS was used to simulate the dynamic process of temperature field.The three-dimensional model of cladding morphology was obtained by the method of life-and-death element method.The effects of temperature rise,laser attenuation,latent heat of phase transformation and the effect of temperature on the thermophysical properties of the cladding powder were investigated.By combining the results of the temperature field with the solidification theory,it is deduced from the shape control factor that the microstructure of the cladding layer along the depth of the substrate surface is equiaxed crystal,dendrite,cellular crystal,and planar crystal.From the cooling rate,it is inferred that the microstructure of the cladding layer is equiaxed crystals < Dendrite < Cell crystal < Planar crystal.The verification test proved the correctness and accuracy of the simulation.(2)through the coaxial powder feeding laser cladding technology,the orthogonal test of different laser power and scanning speed was carried out on the preparation of Ni/WC composite coating on Mn13Cr2.The results show that with the same process parameters,the width of the cladding layer increases with the increase of the laser power,while the height of the cladding layer increases first and then decreases with the increase of the power and then increases.For the scanning speed,the cladding width and height decrease as the scanning speed increases.The laser power should be controlled within the range of 1600 W to 1900 W.(3)A series of characterization tests were carried out by optical microscopy,SEM,EDS,and microhardness tester,and abrasion resistance test of room temperature dry friction and wear was also performed.The results show that the microstructure of the cladding layer along the depth of the substrate surface is equiaxed crystal,dendrite,cellular crystal,and planar crystal.The relationship between the size of the organization is equiaxed crystals < dendritic < cell crystal < planar crystal.This is consistent with the inferred from the simulation;the average micro-hardness of the cladding layer is 2.8,2.5,and 2.3 times that of the matrix,respectively,and the microhardness of the coating is significantly higher than that of the matrix;The wear of the substrate was 10.4 times that of the cladding layer at a power of 1600 W,and the wear resistance of the Ni/WC coating was greatly improved.