Analysis Of Inductive Heating Magnetic/Temperature Field Characteristics At The End Of Billet

The end induction heating is an environment-friendly heating method that uses the induced eddy current to raise the temperature of the end of the billet.It has the advantages of low energy consumption,high efficiency,no pollution and precise control,and is widely used in the production of metal heating process.In the induction heating process,the end effect makes the position of the end of the blank easy to gather the magnetic induction line,which causes the induced current density at the end to be large,and the excessive temperature difference of the heart surface is likely to cause overburning.Based on the principle of electromagnetic induction heating,the numerical simulation of the end-induced heating magneto-thermal coupling based on the change of the induction coil loading current with the billet temperature is carried out by controlling the temperature difference of the end of the billet as the core and combining with the actual production requirements.The main research contents are:(1)The four basic theories of skin effect,proximity effect,ring effect and end effect in electromagnetic induction heating are expounded.The depth and energy loss of the skin layer in induction heating are analyzed.According to the characteristics of the heating system resistance and impedance change caused by the temperature rise of the billet,the variation law of resistance and impedance during induction heating is analyzed.In order to improve the accuracy of magnetic-thermal coupling numerical simulation,a numerical simulation method of magneto-thermal coupling of induction coil loading current with billet temperature is proposed.This method is realized by writing APDL language in ANSYS simulation environment.(2)The characteristics of the induction heating magnetic field and temperature field at the end of the blank were analyzed.Using the numerical simulation method of current variation with billet temperature,the distribution law of magnetic flux at the end face of the billet after induction heating is obtained.The variation of billet center and surface temperature with time in the heating process is analyzed,and the path along each specific position of the billet is analyzed.The temperature changes to the axial direction and the axial direction.The simulation results are basically consistent with the actual production,and solve the problem of solving the magnetic-thermal coupling numerical analysis of the heating process under the condition of dynamic change of induced current.(3)The optimization study of the influence of the coil structure on the uniform temperature of the end face of the induction heating blank was carried out.The effect of the distance between the blank head and the tail of the induction coil on the heating effect was studied.The optimal distance value was obtained according to the diameter of the blank.The effective range of the heating length of the blank under the given coil length was obtained.The variation law of the influence of the constant equivalence interval induction coil and the non-equal spacing induction coil with continuous variation of the pitch of the crucible on the surface temperature difference of the billet end face,and an optimization scheme for changing the uniformity of the heating temperature of the end surface of the billet by the coil structure is obtained,and the induction coil is obtained.The engineering design has certain guiding significance.The influence of the short-circuit ring on the end face temperature of the ingot after the addition of the short-circuit ring is studied.It is found that the short-circuit ring reduces the magnetic flux density in the end region and improves the uniformity of the end face of the blank effect.