Numerical Simulation And Experimental Research Of Thermo-mechanical Coupling Laser Cladding For Rotor Shaft Of Centrifugal Pump

To cope with the complexities of the rotor shaft of centrifugal pumps in the actual working environment and to improve the performance and reliability of the rotor shaft in actual operation,the surface of the rotor shaft needs to be modified to improve its serviceability and load-bearing capacity.Surface modification and strengthening is one of the technical means of laser additive manufacturing,of which laser cladding technology for surface modification and strengthening has the advantages of high material utilisation,green and environmental protection,which can effectively improve the traditional technical means and provide a new road direction for the future development of manufacturing.This paper uses a combination of numerical simulations and experimental analysis to analyse the laser cladding of rotor shafts and to investigate the laws of the cladding process in terms of temperature and stress fields under different models,in order to optimise the process parameters and improve the cladding quality.A three-dimensional finite element model is established with finite element software,boundary conditions and load steps are set,and the dynamic simulation process of laser cladding is realised by combining the heat source model and the "living and dead unit technique" to investigate the temperature field distribution as well as the thermal cycle curve and temperature gradient distribution rules.The simulation will also investigate the stress field distribution and the shape variation before and after the melting process.The optimum process parameters for single-pass cladding are explored by combining cladding experiments and material property testing.The reliability of the models is verified by comparing the simulation models with the cross-sectional morphology of the clad layers,and further simulations and experiments are carried out to investigate the cladding process for different models.The results show that the optimum process parameters are when the laser power is1800 w,the scanning speed is 6mm/s and the powder feeding rate is 15g/min.The residual stresses are distributed at the beginning and end of the clad layer with a maximum residual stress of 196 MPa;the multi-lap temperature field tends to rise gradually,but the heat accumulation is small and a large tensile stress is formed at the end of the clad layer with a maximum residual stress of 317 MPa.The maximum temperature of the melt pool during the cladding of the rotor shaft is approximately 2466°C.The stress field is more evenly distributed and the maximum residual stress is approximately 235 MPa.The average hardness of the clad layer is 256.6 HV0.3,which is a good cladding effect.Coaxiality measurements were carried out before and after the rotor shaft was clad,and the maximum change was 49.31?m,with an error result of 4.6% compared to the actual simulation model,verifying the reliability of the model.