Multiphysics Coupling Analysis Of Sprocket Induction Hardening Process Based On Ansys Software

As an important mechanical transmission part,sprocket is extremely widely used as it has the advantages of fast transmission speed,high efficiency,strong carrying capacity,and small space occupation.The failure of sprocket is mainly caused by surface wear,while induction heating can increase the hardness and wear resistance of the sprocket surface and maintain the plasticity and toughness of the heart,improving the comprehensive mechanical properties of the sprocket.With the development of computer technology,the application of numerical simulation to predict and guide the induction heating process has become more and more common.It is of great guiding significance and practical value to investigate the change process of the temperature,structure and stress of the sprocket induction heating through numerical simulation.This paper explores the finite element numerical simulation of sprocket induction heating,including the following contents:First,based on Ansys,the finite element model of the sprocket was established,which was used for the simulation calculation of the electromagnetic field and the temperature field.The coupling of the electromagnetic field and the temperature field was realized by the sequential coupling method,analyzing the distribution of magnetic induction intensity and induced eddy current in the process of sprocket induction heating.In addition,the effects of current density,air gap and other parameters on the temperature distribution of sprocket induction heating were analyzed.By adjusting the current density and current frequency and from the perspectives of whether the current density changes w ith different frequencies during dual frequency heating and the sequence of intermediate frequency and high frequency heating,two goals were achieved.On the one hand,the characteristics of the dual frequency heating of the sprocket were explored.On the other hand,the distribution of the hardened layer of the sprocket was optimized.Moreover,the role of the cooling coefficient in induction quenching was analyzed.The results show that:during the induction heating process,the magnetic induction intensity and induced eddy current are mainly distributed on the surface of the sprocket,and the distribution layer is shallow;the heating speed becomes faster with the increase of the current frequency,and the change in skin depth is opposite.The sharp corner effect of sprocket induction heating is mainly manifested in the tooth root area.The higher the frequency,the sharper corner effect is more obvious;the greater the current density makes the heating speed faster,the higher the temperature that can be reached by heating at the same time,and the current Density strengthens the sharp corner effect;when the air gap is increased,the heating speed is slowed,and at the same time,the maximum temperature that can be reached is reduced.In the range where the air gap is less than 15mm,the maximum temperature reduction rate and the air gap are "reverse parabola" relationship.Second,by adjusting the current density and current frequency,from the perspective of whether the current density corresponding to different frequencies changes during dual-frequency heating,the order of intermediate frequency and high-frequency heating,the heating characteristics of different combination methods are studied.The distribution of the hardened layer of the wheel has been optimized.In addition,the role of the cooling factor in induction hardening is also analyzed.The results show that a constant current density is difficult to meet the heating needs of medium frequency and high frequency,and the heating effect is not ideal.When the current density changes with frequency,it is easier to heat the tooth root and tooth top at the same time after the intermediate frequency and high frequency heating,but high frequency heating will cause greater interference to the temperature distribution formed during intermediate frequency heating.The heating method of high frequency followed by intermediate frequency realizes different frequencies to heat different areas separately.This method makes it easier to control the temperature and the distribution of the hardened layer.Using this method,the hardened layer distributed along the tooth profile is optimized.The quenching results under different cooling coefficients show that when the cooling coefficient is small,the tooth root is prone to incomplete transformation due to insufficient cooling.Third,the program of austenite phase transformation during heating and the phase transformation of martensite during cooling were written by APDL language.Additionally,in the process of solving the austenite volume fraction,the influence of the heating rate on the austenite start transition temperature was also taken into consideration.According to the phase transformation of the sprocket under different process parameters,the heating effect of the sprocket was analyzed,obtaining a quantitative change in the structure parameters to intuitively judge the distribution of hardened layer after induction quenching.The comparison between the experimental and simulated data shows that the simulated results are in good agreement with the experimental results.Final,the stress field calculation program was written by APDL language,?The physical environment method was applied to calculate the thermal stress,and the strain value related to the phase transition was calculated by the secondary development of Ansys.The strain value was converted into the stress value according to the corresponding rule.Then the stress calculated by the internal and external parts was converted into Ansys through the data.The analysis found that the maximum value of thermal stress in the induction hardening process appeared on the tooth root surface,and the stress was tensile stress.The analysis of the phase transition stress shows that the influence of the phase transition process on the stress distribution is much greater than that of temperature.And when austenite transforms,it is easy to produce tensile stress.By analyzing the effects of temperature and phase transformation on stress distribution,verifying that it was feasible to completely solve the changing process of electromagnetic field,temperature field,tissue field and stress field.