Effect of nitrogen on the size and distribution of ain precipitates in 3% silicon steel

Abstract

Taguchi et al. first utilized AlN and MnS as grain growth inhibitors at the primary recrystallization stage and a nitrogen contained atmosphere at the secondary recrystallization stage to produce high quality grain oriented silicon steels with sharp {l_brace}110{r_brace} texture. Recently, further strengthening of the inhibition was realized by nitriding the final gauge steel sheet prior to the secondary recrystallization process. Though the beneficial effect of the nitrogen has been confirmed, there has not been sufficient understanding how the presence of the element changes the precipitate size and distribution. The authors investigated the size and distribution of AlN precipitates in 3% silicon steels under the influence of nitrogen in the matrix or annealing atmosphere. Final gauge steel sheets of 0.10 mm thickness were nitrided to have various nitrogen content in the matrix ([N]). They were, then, annealed under two different nitrogen partial pressures (100%H{sub 2}, 75%N{sub 2} + 25%H{sub 2}). Samples were taken prior to and at certain intervals during the annealing. Precipitates in the samples were inspected by analyzing the extraction replica images taken by transmission electron microscopy (TEM).