The role of special grain boundaries during the grain growth in Fe-3%Si

Effect of the low temperature annealing on primary and secondary structures and magnetic properties of Fe-3% Si

“…The conventional (CGO-conventional Grain Oriented) and high permeability (HGO) 3%Si steel present a deviation from the ideal Goss texture of 7 and 3°, respectively 1 . The magnetic induction measured at 800 A/m (B 8 ) correlates well with the orientation degree of Goss texture 2 . The typical B 8 results of CGO and HGO steels are 1840 and 1930 mT, respectively 3 .…”

“…• normal grain growth had a harmful effect on the secondary recrystallization: the Goss texture deviation increased and consequently reduced B 8 . Normal grain growth in the samples B and C suppressed the secondary recrystallization; • better magnetic properties after final annealing of the decarburized samples.…”

“…The decarburized sample A presented the typical texture of CGO material, as follows: 28.4% eta, 27.3% gamma and 23.5% alpha 8,[14][15][16] . The decarburized sample B presented gamma fibre (28.4%) stronger than alpha and eta fibres (26.5%).…”

“…They will migrate earlier, allowing Goss oriented grains to grow at lower temperature than other orientations or, in other words, with less dissolution of the inhibitor particles. Taking into account this model, some works suggests that CSL Σ9 and CSL Σ5 boundaries play an important role in growth selection of Goss grains in HI-B and CGO steels, respectively [6][7][8] . The second model is based on the assumption that the high mobility is a feature of the so called "high energy" (HE) boundaries defined as boundaries between grains misoriented by the angle of 20 to 45° [ 3,9] .…”

“…The typical primary texture presents eta and gamma fibres stronger than alpha fibre 8,[14][15][16] . Some works have discussed the main variations which take place in the primary matrix during the heating step in the final annealing, before secondary recrystallization temperature is achieved.…”