Study On Wear-resisting Mechanism Of Bionic Guideway And Dynamic Contact Stress Analysis

In recent years,it has been becoming a hot topic that the combination of laser surface modification technology and bionic coupling theory is widely used in rail wear resistance improvement.But the internal stress in the wear process is still very vague.(1)The NC machine guide was treated by laser melting so as to improve its wear resistance.The micro-morphology,organizational structure,micro-hardness,elastic modulus and 3D wear morphology of HT300 was analyzed before and after laser strengthening.The mechanism of wear resistance after laser melting was summarized from two aspects of microstructure and microhardness.The martensite structure formed by laser melting of the HT300 rail has enhanced the ability to resist plastic deformation because of the interaction between twins and dislocation.Microhardness increased 3.11 times,so the rough peaks in the hardening zone bear the main stress,and reduce the stress of the matrix.Graphite content was reduced by 40%,so the crack initiation rate can be reduced.After laser treatment,wear,cone,scale tail,pitting and spalling were lower than those of the untreated area.The direction of crack propagation is 45 degree with the direction of friction,and the sprout head is the boundary between the matrix and the melting zone.(2)Different bionic specimens were designed and tested under the same rolling dry wear condition.Based on weight loss and 3D morphology,the bionic texture which can largely improve the wear resistance of the guide rail was obtained.Among the blocks with same shape,the larger volume of hardened area,the stronger wear resistance,which is mainly attributed to the high hardness value.While,the blocks with same texture volume has different wear resistance.This phenomenon is due to different equivalent stress,maximum shear stress and frictional stress.(3)The frictional stress of different bionic guide rail was analysed by ansys workbench from three aspects of shear stress,equivalent stress and frictional stress.The results of dynamic contact analysis show that the ability of specimens to resist fatigue wear is basically the same as that in the experimental results.The larger the angle between the bionic texture and the friction direction,the smaller the friction stress.The analysis results show that the textures after pangolins have better resistance than the ones have certain angle with the frictional direction.Bionic specimen can make the frictional stress of the contact surface become smooth,so that the material is under even force.The existence of the bionic texture changes the stress distribution of the moving parts and reduces the maximum stress distribution area.It is easy to produce stress concentration at the angle of bionic texture.While,the arc plays a role in releasing stress.Based on the results,the scheme of optimizing the wear resistance is obtained,which has certain guiding significance for the bionic strengthening of the guide rail.