Numerical and experimental study of stepwise induction cladding

A stepwise induction cladding process was studied using both simulations and experiments. Three types of commonly applied alloy powders were coated onto a grey cast-iron substrate. A coupled electromagnetic and heat transfer model is proposed to analyse the stepwise induction cladding process. From the electromagnetic field and heat distribution, it can be clearly seen that the eddy current, which was generated by the alternating magnetic field, was generally distributed within the coating and the thin layer near the substrate surface, which in turn resulted in Joule heating. The simulation results provide a clear picture of the process of an alloyed coating metallurgically bonding to the substrate, which is difficult to observe experimentally. To verify the numerical calculations, experimental studies on induction cladding under the same process parameters as the simulation were performed. The maximum temperatures on the outside surface of the graphite tube and the substrate were in reasonable agreement with the simulation and experimental results. Finally, the characteristic microstructure, porosity, and hardness of the coatings were analysed.