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Defining the Role of Hot Band Annealing in High-Permeability Grain-Oriented (GO) Electrical Steel
Journal
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
ISSN
10735623
Date Issued
2022-05-01
Author(s)
Giri, Sushil K.
Kundu, Saurabh
Prakash, Aditya
Cicale, S.
Albini, L.
Samajdar, Indradev
Abstract
Pilot plant trials first established that prior hot band annealing (HBA) provided significant improvements to Goss {110}〈001〉 texture and magnetic properties of fully processed high-permeability (Hi-BTM) grain-orientated (GO) electrical steel. The mechanism(s) responsible for such improvements were then explored through laboratory trials on industrially produced hot band (HB) GO. In particular, simulated HBA was shown to generate recrystallized grains with ‘minor’ remnant plastic deformation, but slightly weaker Goss texture in the subsurface. HBA followed by the cold rolling, on the other hand, accelerated the primary recrystallization kinetics and enhanced the presence of through thickness Goss grains. These were related to the more grain interior strain localizations, which dominated post-HBA cold rolled GO microstructures. The most significant effect of the HBA, on the cold rolled plus primary recrystallized microstructure, appeared in the form of noticeably different grain boundary character distribution. Post-HBA cold rolled plus recrystallized Goss grains had a noticeably higher fraction of growth-favorable special boundaries with their immediate neighbor(s). It is hence proposed that a micro-growth advantage or selection, during the early stages of normal grain coarsening, brought out the growth advantage for Goss during the final secondary recrystallization of the HBA specimens.