EFFECT OF AUSTENITE PANCAKING ON TEXTURE FORMATION IN A PLAIN CARBON AND A NB MICROALLOYED STEEL

The way in which texture development is affected by austenite pancaking was studied in a plain carbon and a niobium steel. Three processing parameters (austenitizing temperature, finish rolling temperature and amount of reduction) were varied, and their influence on the state of the austenite was analyzed. It was found that the presence of niobium, which leads to pancaking of the austenite when low finishing temperatures are employed, strengthened the transformation products produced from the copper, brass, S and Goss orientations in the austenite. Larger reductions resulted in sharper textures, especially in the microalloyed steel. The effect of austenitizing temperature was not particularly strong. Several f.c.c. ideal orientations were transformed according to the Kurdjumov-Sachs relationship, and the b.c.c. products resulting from this analysis are compared with the experimental results. When recrystallized austenite transforms, it is shown that the cube component transforms preferentially into the {001}[110] rotated cube orientation, with lower than expected intensities displayed by the Goss and rotated Goss components. Similar trends are observed with respect to the four main deformation components; these tendencies are interpreted in terms of variant selection and selective growth.