Research On The Quality Controlling Process Of The High Frequency Induction Cladding Coating

As a new surface modification technique,the high frequency induction cladding has combined the advantages of induction heating and the composite materials as well as the surface coating technology.It has broad applying prospect in the industrial application for that it can produce coatings with high abrasion resistance,fatigue resistance and corrosion resistance,as well as high hardness at a low cost.The process of high frequency induction cladding is complex as it involves the electric fields,magnetic fields,temperature fields and the stress fields.Currently,this technology is in the initial stage,the cladding process is imperfect.After the process,there will be impurities and pores in the coatings and the coatings would be half-cooked,also the adhesive strength between the coatings and the substrate is not satisfying and the forming quality is greatly affected.In this subject,the thermal-magnetic function applying to the high frequency induction cladding was build,the optimal process parameters for coatings of high quality were researched.Besides,the interaction laws of the coupled fields during the cladding process were expressed.Finally,the process planning strategy controlling the quality of coatings is studied,providing the theoretical basis and data reference for the development of the high frequency induction cladding technology.The main researches and innovations of this subject are as follows:(1)Numerical simulation of the coupling field of the high frequency induction cladding was researched.Aiming at the nonlinearity coupling problems in the high frequency induction cladding,the electromagnetic fields,temperature fields and the residual stress fields during the cladding process were analyzed.The time-depended thermal-magnetic function was build,and based on the finite element analysis software,the function was verified.Besides,the numerical model of the heat resource during the cladding process was established,providing the quantitative comparison method for studying the thermal conducting laws,as well as the reference for establishing the high frequency induction cladding experimental platform.(2)The test platform was building up and preparation technology of coatings was researched.The test platform contains the Induction heating power supply,infrared thermometer,horizontal machine tool,cooling circulatory system and the PLC digit acquisition system.In order to optimize the forming quality of the coat and increase the bonding strength among the substrate and the coat,the theory of selecting the optimal proportion of the alloy powder and the protect loop was proposed,which meet the requirement of process of preparing the coat of high frequency induction cladding.(3)The process parameters of high frequency induction cladding were studied.Orthogonal experiment was designed to find the internal relationship between the process parameters,temperature fields and the coatings,getting the optimal parameters of the process.With the optimal parameters,the forming quality of the coatings and the comprehensive mechanical properties of components were improved.(4)The mapping relationships between the quality of the coat and content of the Rare Earth Oxide as well as repairing groove were researched.For further refining the internal microstructure of cladding layer,promotion on mutual diffusion of elements of substrate and coating and reduction in the number of impurities as well as porosity in the coating,on the basis of the obtainment of the optimal process parameters combination by strengthening the quality of high frequency induction cladding layer,this paper has adopted the practice of adding rare earth oxide(REO)into the cladding powder,so as to explore a better quantitative value of REO content in the coating.After that,in order to further improve the bonding strength of coating and substrate,repair defects such as the pits on axial parts surface,micro cracks,etc.,and to make a quantitative analysis of their maximum indentation depth,suitable for repairing,the paper havs grooved and populated Ni60 alloy powder to perform high frequency induction hot repair,so that we can do research on the mapping relationship between the bond strength of high frequency induction cladding coating and the repairable groove depth.The study provided the more reliable and efficiency numerical model and the basis for experimental method for the quality controlling theory of the high frequency induction cladding.This technology is a new surface modification technique,which is energy and environment friendly.To a certain extent,the improvement and popularization of this technology have the important meaning for the application of the high frequency induction cladding in the field of petroleum and aerospace industry as well as the engineering equipment.