Control Research On The Dilution Rate And Process Optimization In Induction Melting For Preparation Of Ni60 Coating

Induction heating has peculiar advantages for rotational parts,so that is widely used in the field of surface heating treatment.And it is liable to be found that the flow and oxidation for coating,because the existing technology of coating preparation is not enough consummate.At the same time,it is still has no intuitive evaluation standards for quantitative analysis of the coating quality.These problems have become the main factors that severely restrict the development of induction cladding technology.The research work in this dissertation aims at investigating control law about the dilution rate in the process of induction melting and process optimization.The diffusion regularity between coating and substrate is analyzed profoundly and a concept of dilution rate is introduced in the process of induction melting,finding the method for dilution rate control.The research works in this paper are mainly based on the following content:Aiming at the problems flow and oxidation,a new coating preparation technology has been put forward and been called induction melting.The experimental platform is built to induction melting Ni60.The organization of coating and substrate and diffusion phenomenon in them is observed and analyzed.The law of hardness change between the coating and substrate is researched.Based the study on laser cladding dilution rate,a concept of dilution rate in induction melting is put forward and its calculation method is summarized.According to the calculation method of induction melting dilution rate,it can be found that the distribution of temperature field is the foundation of dilution.So on the basis of Maxwell’s equations and under the consideration of the nonlinearity of the material,a thermal field model of induction melting is established and verified,which contains the analysis of phase transition.Compare the distribution of temperature field under various of process parameters and research the changes of temperature field in process of cooling solidification.The law of heat transfer is found in induction melting,which provides the basis for the analysis of molten pool.According to the thermal field model and the governing equations of flow,the model ofmolten pool by induction melting is obtained.The law of molten pool morphology change and movement is researched in the process of heating and cooling.Calculate the distribution of temperature field interior the molten pool and research the flow law of solute in the molten pool.In addition,the law of process parameters on the molten pool’s sectional area and on the internal intensity of flow.Based on the study on the molten pool and calculation method of induction melting dilution rate,the rules of process parameters effecting the dilution rate is studied.In order to analyzing the sensitivity of various factors on the dilution rate and selecting the optimal combination of factors,the orthogonal tests are used to analyze,in which setting residual stress as the auxiliary target parameters.Combining the experimental research,the control method of induction melting dilution rate is found and the process of induction melting is optimized.