Exploitable results
An attempt was made to apply rapid transverse induction heating to three major stages of electrical steel production. The market and the economics of electrical steels produced by the conventional processes have been evaluated and potential for improvement have been identified. Magnetic and mechanical properties as functions of processing parameters (including rapid heating rates, peak temperature and holding time) were examined. Vast amounts of data were produced by interrelating magnetic properties of the electrical steels to heat treatment conditions utilizing the whole range of heating rates available. For non oriented steel, in general specific loss decreased with the increase of heating rate and peak temperature. Polarization increased with the increase of heating rate and decreased with the increase of peak temperature. The effect of heating rate on loss reduction was more profound in medium silicon alloys such as those with silicon content of 1.3% and 1.8%. Rapid heating has also been shown to reduce the magnetic anisotropy of non oriented steels. For regular grain oriented material, results indicated a potential for loss reduction by applying rapid heating as part of decarburization annealing during the production process. A new method of magnetic measurement of flux distribution in limited area was developed and the effect of the magnetooptic Kerr effect was observed in non-oriented steel. Transverse flux induction heating technology was developed for electrical steels. Design data for the inductor was tuned according to the specific physical properties of the electrical steels and a full set of operating parameters of the laboratory-scale transverse flux induction heating (TFIH) line for electrical steel strips were formed and finally a computer programme was developed for transformer optimization by calculation of the set of design parameters that defines the cheapest transformer which fulfils all functional requirements.