Research On Numerical Simulation And Experiment Of Laser Cladding For Piston Rod Of Hydraulic Damper

In order to attenuate the adverse impact of railway impact and vibration on rolling stock and improve the safety and comfort of rolling stock,hydraulic damper is often used in modern rolling stock to meet the actual functional requirements.Piston rod is an important component of hydraulic damper,and in the bad working environment,its should haves high wear resistance and corrosion resistance.At present,there are serious pollution problems in the production process of the piston rod surface treatment methods such as chromium plating and thermal spraying.The coating by the traditional method is easy to peel off.Therefore,it is urgent to explore a green manufacturing technology for surface treatment of the piston rod of hydraulic damper.Laser cladding technology is a green manufacturing technology.It is not only pollution-free in the production process,but also can achieve high-strength metallurgical combination between cladding layer and metal substrate.Therefore,the laser cladding technology by used for the surface treatment of piston rod of hydraulic damper was proposed,and its technical feasibility was studied,which would provide theoretical support for promoting the application of laser cladding technology.The laser cladding process of the piston rod of hydraulic damper was studied by combining the methods of finite element numerical simulation and experiment.The main research work includes the following aspects:?1?Considering the parameters of material thermal physical property,parameters of laser heat source and the actual conditions of workpiece rotation,laser beam horizontal movement along the workpiece cylinder surface during laser cladding process of piston rod of hydraulic damper,the finite element model of the synchronous laser powder cladding process for the piston rod of hydraulic damper was established by using Visual Environment and SYSWELD software system.To check heat source was done by the molten pool morphology comparison,Make the morphology of the molten pool obtained by numerical simulation and experiment basically consistent.In order to obtain more accurate heat source parameters.Through simulation analysis,the distribution law of temperature,metallographic structure and microhardness of the cladding layer is obtained.The research results show that the temperature peak and gradient of the deeper area from the surface of the cladding layer in the direction of the substrate,the ratio of martensite structure and The microhardness decreases gradually.?2?The influence of different process parameters?laser power and scanning speed?on the temperature distribution and change of laser cladding process and the change of weld pool size were analyzed by numerical simulation,and the influence of process parameters on the quality of cladding layer was discussed.The simulation results show that when the scanning speed and laser spot diameter are constant,the peak temperature and pool depth of cladding layer increase and the dilution ratio increases with the increase of laser power;and when the laser power and laser spot diameter are constant,the peak temperature,pool depth of cladding layer and the dilution ratio decrease with the increase of scanning speed.?3?Four groups of typical process parameters were selected for laser cladding experiment,and the micro observation of laser cladding pool morphology and size,as well as micro hardness test were carried out.Compared with the simulation results,the test results was much more consistent with the simulation results,and the average microhardness of cladding layer of piston rod of hydraulic damper in the process scheme1?laser power P=1500W,and scanning speed V₁?meets the relevant technical requirements of the piston rod.According to the requirements of GB/T 10125 and GB/T6461,the salt spray test was carried out on the cladding layer.The test results showed that the corrosion resistance of the laser cladding layer was excellent and its meets the technical requirements of the piston rod.The research results showed that the surface treatment technology of laser cladding on the surface of piston rod of hydraulic damper was feasible.