Formation of {100} texture in 2.3%Si-0.1%Mn steel strips by short-time annealing and their magnetic properties

Electrical steels, which consist of {100} columnar grains with the easiest magnetization direction of <;001> and thus can serve as the ideal cores of electrical motors, have been recognized for the last half-century. It was pointed that the {100} texture can be obtained through a high temperature annealing of very thin silicon steels [1] or under a hydrogen atmosphere containing a small quantity of H₂S [2]. The formation of the {100} texture has been understood in the light of the surface-energy-induced selective grain growth in which the surface energy of the {100} plane is lowest [3]. Meanwhile, it has been shown that a decarburizing annealing gives rise to a remarkable evolution of the {100} texture [4,5]. The change in chemistry causes not only austenite to ferrite phase transformation but also the selective growth of the formed {100} ferrite grains. However, the commercialization of such processes have failed due to two factors: the annealing atmosphere (i.e., vacuum) not appropriate for the commercialization and the annealing time of about 10 h or longer. In this study, a revolutionary method for forming the {100} texture is introduced. This method consists of 2.3%Si-0.13%Mn steels in which, unlike the situation in the researches [4,5], carbon is only included as an impurity, conventional cold rolling, and two-steps final annealing within the total annealing time of 5 min in the temperature range of 850-1300°C under a reduction annealing atmosphere.