The Control Systems Design Based On Simulation Of Temperature Field In Induction Remelting And Research On Modified Ni60 Coatings

In the process of steel rolling production,working rollers such as furnace bottom rollrer and conveying roller are in direct contact with red-hot steel plate.After long-term operation,the surface of the roller will produce a large number of cracks,drop defects and failure.Therefore,it is very important to repair and strengthen the damaged working roller's face by adopting proper surface engineering technology.Compared with thermal spraying,surfacing welding,induction remelting technology has unique advantages in repairing and strengthening metallurgical roller surface.However,the traditional induction remelting equipment is based on manual observation and low degree of automation.Due to induction remelting process is affected by the electromagnetic-thermal coupling field,it is difficult to use accurate mathematical formula to accurately analyze the heating process.During induction remelting process,it demands higher for the operator technology level,the operator needs to judge the remelting condition of the workpiece surface by the"mirror effect"on the workpiece surface.At the same time,the metallurgical roller is subjected to strong wear and high temperature corrosion,so the conventional Ni60 alloy coating is difficult to meet the requirements.In view of the problems existing in the induction remelting technology,this paper conducts relevant research in the following aspects.In the first part,the multi-field solution method of ANSYS software is adopted to simulate the induction remelting process.By establishing the geometric model,defining the element properties,determining the grid division form and some relevant boundary conditions,the influence of the changes of induction remelting current,frequency and clearance process parameters on the workpiece surface temperature is simulated and calculated.The results of numerical calculation of induction remelting is analyzed.At the same time,an experimental platform is set up to verify the influence of remelting parameters on the surface temperature of workpiece.The results show that the experimental results are in good agreement with the simulation results,which verifies that the numerical simulation research can provide some data support for the actual induction remelting condition.In the second part,based on the analysis of induction remelting process,the overall design scheme of automatic induction remelting control system is determined.In this scheme,the hardware structure design and model selection of the corresponding equipment are completed through the control technical requirements and performance indicators of each subsystem to be realized,and the relevant circuit diagram of the control system of the induction remelting is designed at the same time.Finally,the software design of PLC control program is completed on the basis of hardware selection,and the interface of parameter setting and operation is written on the touch screen.Equipment debugging proves that the system has fast response,good stability and can meet the production demand.In the third part,the effect of CeO₂ on microstructure and properties of Ni60 alloy induction remelting coating is investigated.Firstly,the Ni60 alloy powder containing CeO₂ with different mass fractions of rare earth oxides is sprayed on the surface of 45#steel by flame spraying technology,and then the pre-sprayed coating is processed by induction remelting.The microstructure and composition of the remelting coating is observed and analyzed by metallographic microscope,scanning electron microscope and X-ray diffraction,the hardness,wear resistance and corrosion resistance of the remelting coating is tested by microhardness tester,wear tester and electrochemical workstation,and the effects of rare earth oxide CeO₂ on the microstructure and properties of the remelting coating is discussed.The results show that the remelting coating with appropriate amount of rare earth oxide CeO₂ can refine the grain structure of the remelting coating,make the structure compact and uniform,and improve the microhardness,wear resistance and corrosion resistance of the coating compared with the remelting coating without CeO₂.However,the remelting coating with excessive rare earth oxides CeO₂ will make the grain size of the remelting coating larger and the performance decreased.