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 utilising the whole range of heating rates available.
For non oriented steel, in general specific loss Ps decreases with the increase of heating rate and peak temperature. Polarisation J increases with the increase of heating rate and decreases with the increase of peak temperature.
The effect of heating rate on loss reduction is 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 indicate a potential for loss reduction by applying rapid heating as part of decarburisation 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.
A computer programme was developed for transformer optimisation by calculation of the set of design parameters that defines the cheapest transformer which fulfils all functional requirements.
The proposed research is directed towards the production of novel, low loss, electrical steels by the modification of grain growth and recrystallisation utilising controlled and rapid heating rates. This will involve the development of a new heat treatment scheme for the production and processing of electrical steels using novel heating rates through the application of transverse flux induction heating techniques. It is expected to achieve the reduction in the cost of low loss electrical steels by establishing a cost effective process.
The major research tasks are:
1. Determine the relationship between heating rates and the changes in the metallurgical structure of silicon steel sheet for magnetic devices.
2. Develop a heat treatment technology to optimise the magnetic properties of the steels.
3. Investigate a potential production route for the novel steel materials.
4. Reduce the cost of low loss magnetic materials.
5. Examine the effect of these novel materials on transformer and motor performance and design.
The success of this project will also lead to considerable reduction of the energy expended in transformer and motor cores. This will strengthen the technological base of the European manufactures, reduce the emissions of carbon dioxide and delay the construction of unwanted power stations.
Funding SchemeCSC - Cost-sharing contracts