Papers by Keyword: Fe-3%Si Steel

Abstract: Hot bands of Fe-3%Si steel containing 0.24%Cu were characterized to examine the precipitation of copper sulfides following different heat treatment schedules. It was found that copper sulfides were dominantly in a sphere shape. From 950°C to 1050°C, the precipitates were the complex of copper sulfides and aluminum nitrides. The size of the precipitates decreased and the distribution increased as the temperature increased. However, from 1050°C to 1150°C, the precipitates size increased and the distribution decreased with the rise of temperature. The precipitates were mainly complex copper-manganese sulfides. When the sample was annealed at 1050°C, air cooled to 900°C and boiling water quenched, the most fine and disperse precipitates were obtained. The average size and distribution of the precipitates was 37nm and 2.72μm-2, respectively.

Abstract: The distribution of the precipitates on the grain boundaries in Fe-3%Si steel during secondary recrystallization annealing were studied using high-angle annular dark filed (HAADF) scanning transmission electron microscopy (STEM). Because HAADF image can show both grain boundaries and precipitates clearly, the change of precipitate distribution on grain boundaries can be quantitatively analyzed. It was observed that the total area of the precipitates on grain boundaries increased in the order of non-annealed, 600°C, and 900°C sample and the total area of precipitates on grain boundaries in the 1000 °C sample was much lower than that in the 900 °C sample. The compositions of the precipitates were also analyzed using X-ray energy-dispersive spectrometer (XEDS). The most precipitates were multi-phase ones, mainly composed of AlN and MnS. Our analysis results suggest that such a precipitate behavior is responsible for the abnormal grain growth of Fe-3%Si steel occurring under the temperature above 900 °C.