GO silicon steel is one of the most widely used as core material in transformers and exhibits excellent magnetic properties which are closed related to the sharpness {110} 〈001〉 (Goss) texture [1]. In the past decade, the focus of research in grain-oriented (GO) silicon steel was aimed at increasing magnetic induction and reducing iron loss without increasing the production cost, which has significant contribution in reducing electrical consumption and protecting the global environment [2] and [3]. Thin gauge GO silicon steel is an effective approach to meet the requirements of core material for high-frequency transformers, which has obvious advantages of high saturation magnetization over nanocrystalline materials, even though there are some difficulties associated with processing, particularly in terms of formability and stable secondary recrystallization [4], [5] and [6]. It is generally difficult to produce grain-oriented silicon steel sheets of thickness less than ~ 160 μm by secondary recrystallization induced by inhibitors, because the annealing atmosphere and surface condition have an obvious influence on the ripening of inhibitor [7]. Recent attempts to solve the dilemma have led to two primary approaches. The first approach is based on the retention of Goss texture, where secondary recrystallized silicon steel was rolled to less than 0.10 mm thick and subsequently annealed in vacuum to obtain sharp Goss texture [8] and [9]. The second approach involved multi-stage cold rolling with intermediate annealing and high temperature annealing of pure Fesingle bondSi hot rolled sheet. The driving force for selective grain growth of (110) [001] is the difference in surface energy between (110) and other planes, and is known as surface energy-induced tertiary recrystallization [10] and [11]. Unfortunately, these techniques are far from industrial applications on a large scale due to high production cost, the environmental impact and the limited product size of products fabricated in above approaches.
While a significant effort is being made to develop an appropriate process, a cost-effective process to produce thin gauge GO silicon steel with superior magnetic properties has not yet been developed and requires further research. In this regard, the novel advanced and energy-efficient process, strip casting technology, provides a promising possibility to produce steel that eliminates continuous casting, high temperature reheating, and multi-pass hot rolling, adopted during conventional processing [12], [13] and [14]. Strip casting progress has attracted significant attention to manufacture steels over the world and shows a great potential advantage in texture control over conventional process [15]. Most of the corresponding investigations focus on the fabrication technique of non-oriented or regular thickness GO silicon steel in the recent years [16], [17], [18] and [19]. Moreover, thin gauge GO silicon steel processed by strip casting process has not been explored to the best of our understanding.
In the present study, a 0.08–0.15 mm thick GO silicon steel with high permeability was successfully processed by strip casting, and involved normalizing, two-stage cold rolling with intermediate annealing, primary recrystallization and secondary recrystallization annealing. The evolution of microstructure, texture and effect of inhibitor are elucidated during different processing stages.