EFFECT OF SECOND PHASE PARTICLES TOPOLOGY ON THE ONSET TEMPERATURE OF ABNORMAL GRAIN GROWTH IN Fe - 3%Si STEELS

Electrical steels are undoubtedly the most important soft magnetic materials in use today. Applications vary in quantities from the few ounces used in small relays or pulse transformers to tons used in generators, motors, and transformers. There are two principal types of electrical steels: grain oriented and non-oriented steels. The grain oriented (GO) electrotechnical steel sheets are widely used as core material in transformers, large rotating machines and other electrical equipments. For high magnetic induction and low core losses during premagnetization, this type of steel should have a sharp so-called Goss texture 110 <001> in the final state. This kind of texture provides favorable magnetic properties of the steel in the rolling direction (RD) 1 . Other type of electrical steels is non-oriented steel used in electric machines to transform mechanical energy into electrical energy and vice versa. The 100 orientation plane parallel to surface is a special feature of this kind of electrical steel which provide approximately the same magnetic properties in all directions of the sheet plane 2 . The Goss texture (110) 001 is a result of conventional technological rout applied for Fe-3%Si steels. Two essential requirements have to be fulfilled to foster the process of secondary grain growth: 1) the grain growth inhibitors such as MnS, AlN or MnS+AlN and etc., must be added; 2) the completely recrystallized microstructure with sufficient intensity of Goss texture component has to be obtained before secondary recrystallization 1,3 . The increase in the number of precipitates, change in grain size as well as texture state are account for magnetic properties change in material. The magnetic properties are characterized by coercive force HC. This physical value drastically decreases with commencement of secondary recrystallization because of significant changes in microstructure and texture. The secondary recrystallization starts at particular temperature called an onset temperature of the secondary recrystallization TSR. The intention of current study is to investigate the influence of inhibition system on the TSR in Fe-3%Si grain-oriented electrical steels.