Study on primary recrystallization behavior of Fe–3%Si–Cu alloy with copper-rich precipitates as main inhibitor

In order to break through the bottleneck of high energy consumption in the production of traditional grain-oriented electrical steel, this paper creatively proposes a new composition system of grain-oriented electrical steel with Cu-rich precipitates as main inhibitor. In this research, the microstructure, texture, precipitates and decarburization effect of the primary recrystallization samples are analyzed in the process of decarburization annealing treatment at 850–900 °C for different time. The results show that with Cu-rich precipitates as main inhibitor, the annealing temperature has a great influence on the decarburization effect. The decarburization effect at 850 °C is the best, followed by 875 and 900 °C. The residual carbon content decreases first and then tends to level off with the increasing decarburization time. The optimal process is decarburization annealing at 850 °C for 6 min, in which case the carbon content can be reduced to less than 40 ppm, and the average grain diameter is about 16.1 μm. The primary recrystallized textures mainly include {111}<112>, {111}<110>, {114}<418>, {112}<110> and a small number of Goss-oriented grains. In the decarburized annealed matrix, the Cu-rich precipitates are about 10–50 nm in size, with a distribution density of about 5.06 × 109/cm2, and thus can be used as an effective inhibitor for grain-oriented electrical steel. When the sample is annealed at a high temperature, above 1000 °C, the large-scale secondary recrystallized macrostructure of the steel is formed, more importantly, there is no need for a long purification heat treatment at 1200 °C.