Research On New Induction Boronizing Technology Of Axial Special-shaped Structure Based On Multi-field Coupling Effect

Boronizing is a surface treatment technique,often used to improve the service life and performance of H13 hot die steel.In order to improve the shortcomings of the traditional boronizing process such as long treatment time and poor surface properties,induction boronizing as a special boronizing treatment technology has attracted widespread attention,and the new induction boronizing technology developed based on this technology has the characteristics of double temperature control and rapid boronizing,which solves the shortcomings of single temperature control method and slow boronizing speed of traditional induction boronizing.In this paper,the new induction boronizing technology was used to obtain the ideal boronizing layer for the axial special-shaped H13 steel workpiece,and the multiple physical factors involved in the experiment were studied.The magnetic field,temperature field and concentration field directly affect the thickness and quality of the boronized layer.The oscillating current and frequency output by high-frequency UHD heating equipment will change its magnetic field strength,thereby affecting the temperature inside the container;The change of temperature is bound to affect the chemical reaction rate of boron atoms and borides produced by boronizing agent,resulting in boron concentration gradient,which in turn affects the growth rate of the permeable layer.Due to its built-in spiral structure,the new type of induced boron can enhance the external magnetic field strength of the workpiece,increase the heating rate of the workpiece and the boron atom concentration in the boronizing agent.In this project,the coupling relationship between the fields of each factor is studied,and the monitoring of each field is realized by controlling equipment parameters,temperature measurement and control,and the temperature,concentration and magnetic induction intensity of the experimental topic are simulated and analyzed by using Comsol Multiphysics,Matlab and other software.The thickness of the boride layer,hardness,microstructure morphology,and the content and type of boronized layer of the permeated workpiece were studied by metallographic microscope,microscopic Vickers hardness tester,scanning electron microscopy(SEM),energy spectrometer(EDS)and X-ray diffractometer(XRD),and the simulation results were further verified.After experimental research and analysis,the boride layer growth rate of the new high-frequency induction boronizing technology is much higher than that of solid boronizing and traditional induction heating boronizing,and the thickness of the boronizing layer can reach more than 200μm in a short time,and its hardness can reach more than 1800HV.The concentration of boron atoms in the osmotic agent can reach more than 10%,and the diffusion coefficient of boron in H13 steel can reach about 10000μm2/min.