Finite Element Simulation Of Quenching Process Of Large Wind Power Main Shaft

With the introduction of new energy development strategies,wind energy has received extensive attention as a clean energy source in the world,and wind power related technologies have developed rapidly.The 42CrMo4 steel large-scale wind power hollow spindle is the core key component of wind power generation equipment,and its quality and performance have a decisive influence on the performance of the wind turbine.In this paper,the heat treatment process of large hollow wind power spindle is studied,and the TTT curve,phase transition dynamics and relationship between microstructure and properties of 42CrMo4 material are studied.The phase transition kinetics model,thermal property parameters and mechanical properties database of 42CrMo4 material were established.The temperature-tissue-stress multi-field coupling model was combined with the experimental results to analyze the microstructure evolution,temperature field distribution and stress of the material during heat treatment.The field evolution reveals the cause and complexity of quenching crack formation.The heat treatment process is developed and optimized for large hollow spindles.On the basis of multi-discipline,the phase change kinetic model and numerical simulation calculation model of mixed phase 42CrMo4 material are calculated by JMatPro simulation software,such as supercooled austenite isothermal transformation kinetic curve(TTT curve),temperature-dependent stress.Strain curve,heat capacity,thermal conductivity,hardenability curve,Poisson’s ratio,electron emissivity,etc.,and through the introduction of similar materials,enrich the relevant characteristics of the phases involved in the quenching process,through the finite element simulation software Deform-3D has established a k-file describing the quenching process of the wind power main shaft 42CrMo4,established a complete quenching simulation database,and selected the appropriate TTT curve by combining the same material 42CrMo4 sample test and physical simulation,that is,considering the C curve of the medium temperature transition,It is narrower than the phase transition region of the ordinary C curve.The cooling characteristic curves of 42CrMo4 under different quenching media were determined experimentally.Based on the relationship between the cooling characteristic curves and the surface heat transfer coefficient under quenching conditions,three different surface heat transfer coefficients of different quenching media determined by comparison method,numerical method and anti-heat transfer method were introduced.The cooling characteristic curve of the near surface of the workpiece was determined after the subsequent direction of the anti-heat transfer method pointed out through the anti-heat transfer module of Deform-3D software,,but the results are still instructive.By comparing the simulation results with the actual hardness results,it is determined that the numerical method is more realistic than the heat transfer coefficient obtained by the analog method.The guiding role of the database built in this research was determined by combining the three physical changes of the small physical simulation,the actual heat treatment process,the metallographic phases at different positions of the sample,the SEM pictures and the hardness change curve,paving the way for the large axis simulation.The variation of temperature field,microstructure field and stress-strain field during the quenching process of wind power main shaft 42CrMo4 was analyzed.The influencing factors of stress change during the whole process were studied.The volatility in the early stage of quenching stage was relatively large.After stabilization,it was mainly affected by structure stress and the effect of heat stress was relatively large in the later stage.The effects of different quenching process parameters including austenitizing temperature,pre-quenching time before quenching,medium temperature(quenching medium and air),quenching time of different media on quenching performance of 42CrMo4 were analyzed,and process optimization was carried out based on the influence of process parameters.The direction of heat treatment research can be turned to alternate cooling of water and air.The grain size test at different positions indicates the disadvantage of numerical simulation that cannot fully considered the inhomogeneity of the workpiece and the room for improment of numerical simulation that calling property files with different parameters at different locations by Secondary Developm.