E. Baake, H. Schülbe, A. Nikanorov, Institute for Electrothermal Processes, Hannover, Germany; R. Mergen, A. Eberhard, Miba Bearing Group, Laakirchen, Austria
Induction heating offers numerous possibilities in improvement of existing industrial techniques and in development of new technological processes. Some of the major advantages of induction heating are the fast heating-up rate, the exact temperature control and the predictable spatial and time depending temperature distribution in the workpiece.
This paper describes how induction technology is used to realize a smart gradient heating effect, which leads to a number of technical and economical advantages for multi-layer material processing. The cooling gradient effect inside the workpiece can be used to get a desirable material structure, like oriented crystallization, or an excellent bonding of the multi-layer material. In addition the induction heating gradient effect leads to reduced energy consumption due to the localized heating up of the workpiece.In order to apply and optimize the induction heating gradient effect a two-dimensional transient numerical model of the heating and cooling process for multi-layer flat materials has been developed. Electromagnetic and thermal analysis are coupled to take into account all non-linear influences like temperature dependent material properties, liquid-solid phase transformation and thermal losses by radiation and convection. The reliability of the presented modeling approach has been validated with experimental data carried out from laboratory and industrial lines.
The results and examples presented in this paper will show how the gradient heating and cooling effect depends on various process parameters, like thickness, feed rate and material properties of the multi-layer materials.
Along various industrial applications, e.g. the sinter-casting process of bronze powder on steel strips and the casting of melt on steel strips, it will be demonstrated how the self developed numerical model is used successfully to investigate the time-dependent heating and cooling behavior in order to optimize theses industrial processes.
