Mechanism of secondary recrystallization of Goss grains in grain-oriented electrical steel

• Published in: Science and technology of advanced materials Vol. 18; no. 1; pp. 480 - 497
• Main Author: Hayakawa, Yasuyuki
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 01.01.2017; Taylor & Francis Ltd; Taylor & Francis Group
• Subjects: 106 Metallic materials; 206 Energy conversion / transport / storage / recovery; 40 Optical, magnetic and electronic device materials; Batch annealing; Electrical steels; Grain growth; Grain size; Grain-oriented electrical steel; High temperature; inhibitor; Optical, Magnetic and Electronic Device Materials; Precipitates; primary recrystallization; Review; Rolling direction; Secondary recrystallization; texture; 106 Metallic materials; grain growth; primary recrystallization; 40 Optical, magnetic and electronic device materials; inhibitor; texture; Grain-oriented electrical steel; 206 Energy conversion / transport / storage / recovery; secondary recrystallization
• ISSN: 1468-6996; 1878-5514
• DOI: 10.1080/14686996.2017.1341277

Since its invention by Goss in 1934, grain-oriented (GO) electrical steel has been widely used as a core material in transformers. GO exhibits a grain size of over several millimeters attained by secondary recrystallization during high-temperature final batch annealing. In addition to the unusually large grain size, the crystal direction in the rolling direction is aligned with  , which is the easy magnetization axis of α-iron. Secondary recrystallization is the phenomenon in which a certain very small number of {110} (Goss) grains grow selectively (about one in 10 6 primary grains) at the expense of many other primary recrystallized grains. The question of why the Goss orientation is exclusively selected during secondary recrystallization has long been a main research subject in this field. The general criterion for secondary recrystallization is a small and uniform primary grain size, which is achieved through the inhibition of normal grain growth by fine precipitates called inhibitors. This paper describes several conceivable mechanisms of secondary recrystallization of Goss grains mainly based on the selective growth model.