Optimization Of Carburizing And Quenching Heat Treatment Of Spiral Bevel Gear Based On Multifield Coupling Simulation

The tooth surface geometry and meshing theory of spiral bevel gears are very complex,which is always a difficult problem in the process of manufacturing.On the one hand,on the one hand,the tooth surface quality requirements are very high;on the other hand,it is necessary to have a high wear resistance and high resistance to contact fatigue and bending fatigue performance.Nowadays,the automobile industry usually adopts carburizing quenching surface hardening technology to improve the mechanical properties of parts.However,in the quenching process,the uneven flow of the cooling medium,the change of the microstructure and the thermal stress will cause the distortion and deformation of the parts,and reduce the geometric precision.In the past,the study on the heat treatment of the spiral bevel gear is focused on the influence of the thermal strain and the strain on the geometric precision of the workpiece.This simplified method is suitable for the situation of uniform flow field distribution and simple geometry of the workpiece in the quenching tank,but it has some limitations for the prediction of the cooling history of the complex structure parts.The results show that the heat transfer coefficient of quenching cooling stage has a great influence on the simulation results.In order to reduce the spiral bevel gear heat treatment distortion,and understand the evolution of the heat treatment process of tissue stress and straindistributions,use the following methods to study considering the cooling medium flow spiral bevel gear carburizing and quenching:(1)Establishing the spiral bevel gear and the existing quenching tank model by 3D software UG,using the fluid dynamics software CFX on the existing distribution of cooling medium flow field in quenching tank is studied,by influence of flow field distribution inside the tank and related factors.(2)On the basis of the above research,a uniform flow field distribution scheme is proposed,and the flow field distribution of the quenching tank is obtained;Considering the heat transfer coefficient of the cooling medium flow as the background in the quenching tank under multi field coupling calculation of dynamic thermal boundary conditions,the multi field coupling simulation of carburizing and quenching medium flow is considered to be calculated,and improve the simulation accuracy of prediction.(3)Predict the material properties of low carbon alloy steel 20 CrMoH by materials forecast software Jmatpro,use heat treatment simulation software Deform-HT to simulate the consideration of carburizing and quenching cooling medium flow,analyzes the evolution oforganization change,temperature in the carburizing heat treatment of spiral bevel gear,the distribution of carbon element the microstructure,distribution,distribution of hardness,residual stress and thermal distortion of information,provide the reference for the heat treatment process parameter adjustment.The simulation results of heat treatment show that the top of the teeth after quenching can form a bulge.(4)In order to ensure the hardness of the tooth surface and shorten the length of the drum,using orthogonal test of carburizing and quenching heat treatment process on the impact of considering the medium flow optimization,with medium temperature,entrance velocity,heat preservation temperature and diffusion of carbon potential as test factors,drum length and tooth surface hardness test of heat process parameters are optimized to obtain the optimum process parameters,the optimal flow distribution and heat treatment process of two aspects to improve the existing level of heat treatment.In this paper,the flow field and heat treatment parameters are optimized in two aspects,and the result is good.