Research On Surface Repair Process Of Rail Train Wheel Based On Submerged Arc Overlay Welding

With the rapid development of China’s rail transportation industry,wheel damage,especially wheel surface wear,has increasingly prominent.Repairing wear damage to the surface of railway wheels and improving the wear resistance of wheel materials have become the focus of research.As an environmentally friendly reprocessing technology,submerged arc cladding can effectively repair wear damage on mechanical parts.Therefore,on the basis of the submerged arc hardfacing welding technology,the repair process for wear damage on the wheel surface of a rail train was studied,and the weld hardfacing repair quality was determined and analyzed by considering the melt quality of the hardfacing joint and the mechanical properties related to the evaluation index.The following research contents were mainly studied:（1）Influence of process parameters on the melt quality and the mechanical properties of build-up compounds.By changing the horizontal parameters of welding current,welding voltage and welding speed,the single factor experiment was designed to study the change rule of weld shape and size,microstructure,microhardness and impact strength of the surface joint,and to analyze the reasons for the change of melt quality and related properties of the application joint.The results show that with the increase of the welding current and welding voltage,the microstructure is gradually refined,the microhardness first decreases and then increases,and the impact strength first increases and then decreases.With increasing welding speed,the microstructure and graining of weld overlay gradually increase,the microhardness first increases and then decreases,and the impact resistance gradually decreases.（2）Influence of process parameters on the wear resistance of weld overlay.The ring-block friction and wear tests were carried out on the surface layer obtained under different process parameters,and the effects of the process parameters on the friction coefficient of the wear surface,the occurrence of the wear mark,and the amount of wear before and after wear were examined.The results show that the wear resistance of the cladding layer is obviously better than that of the substrate material,and with the increase in welding current and welding voltage,the wear resistance first increases and then decreases.As the welding speed increases,the wear resistance first decreases and then increases.（3）An orthogonal experimental design was performed to investigate the optimal combination of process parameters.The three-factor,three-plane orthogonal test was developed to analyze the degree of influence of process parameters on microhardness,impact toughness and wear resistance of hardfacings.The optimal combination of process parameters was determined through comprehensive equilibrium analysis.The results show that the welding current is the most important factor affecting the microhardness and impact resistance of weld overlay.The welding speed is the main factor affecting the wear resistance of weld overlay.The optimal combination of process parameters is:welding current 320 A,welding voltage 34 V,welding speed 33 cm/min.Under these parameters,the average microhardness of weld overlay is 340.2HV_10.0,the amount of wear is 0.054g,and the shear cutting rate of impact strength reaches 60%.In summary,the use of submerged arc surfacing welding technology can effectively solve the problem of wear damage on the surface of rail train wheels,and through the research on surfacing repair process,an optimal process parameter combination is obtained,which can provide a certain leadership in the repair of Wear damage to railway wheels.