Simulation of Line Annealing of Type 430 Ferritic Stainless Steel

Abstract

The annealing behavior of cold rolled Type 430 ferritic stainless steel is the subject of this paper. The steel was cold rolled 79%, then heated at 6 °C/s to the soaking temperature of 841 °C, which is just below the Ae1temperature. During heating, specimens were quenched from selected temperatures between 650 and 841 °C and after various times at 841 °C. These quenched samples underwent metallographic examination and micro-hardness determination. The results indicated that under the prevailing experimental conditions, the hardness appeared to correlate strongly with the extent of recrystallization. The kinetics of recrystallization appeared to originate in the cold worked state, where three kinds of grain were found: (i) smooth elongated, featureless of α-fiber orientation {001}<100>; (ii) irregular fishbone grains of the γ-fiber orientations {111}<112> plus {111}<110>; and (iii) twisted grains of the η-fiber orientation {001}<100>. It was found that the twisted grains of the η-fiber were the first to recrystallize, with the fishbone grains of the γ-fiber second, and the smooth elongated, featureless grains of the α-fiber last. It was found that the grains of the α-fiber orientation {001}<100> and the η-fiber orientation {001}<100> were replaced with grains of the γ-fiber orientations as recrystallization progressed. These results are discussed in terms of recrystallization and texture development.