Permanent Magnet Heater for a Precise Control of Temperature in Aluminum Billets before Extrusion

Abstract Aluminum billets are heated at a prescribed temperature before hot working in gas or induction or resistance furnaces. Temperature distribution variable along the billet axis, or 'taper profile' with the initial section hotter than the final part of the billet, improves the extrusion process (isothermal extrusion). Taper temperature distribution is typically realized in induction heater thanks to the accurate control that this technology allows in thermal processing. Permanent Magnet Heaters, PMH, have been recently proposed as a high efficiency solution for the heating of electrically conductive materials. The optimal design of a Permanent Magnet Heater is presented with reference to a real industrial case. The design has been carried out by means of transient magnetic and thermal 2D and 3D Finite Element Models coupled with multiobjective optimization algorithms

Multi-physics and multi-objective design of a benchmark device: a problem of inverse induction heating

In the paper, a bi-objective optimization problem characterized by a multi-physics field analysis is investigated. The optimal design of a pancake inductor, related to the design of industrial devices for the controlled heating of a graphite disk is considered as the benchmark problem. The expected goal of the optimization process is to improve temperature uniformity in the disk as well as electrical efficiency of the inductor. The optimized device is designed using a multi-physics problem: magnetic problem for electrical efficiency computation and thermal problem for temperature uniformity computation. The solution of the relevant bi-objective optimization problem is based on a modified multi-objective genetic algorithm in the class of Non-dominated Sorting Genetic Algorithm. The proposed algorithm exploits the migration concept to vary the population genetic characteristics during optimization process in order to improve the Pareto front approximation

Simple 3D fem models for evaluation of EM exposure produced by welding equipments

In the paper, simplified numerical models of human body are applied for the evaluation of current density induced by strong magnetic field generated by arc welding equipment in order to verify the respect of the basic restrictions proposed by ICNIRP guidelines. Magnetic flux density has been also measured to assess the numerical model