PRIMARY RECRYSTALLIZATION IN A GRAIN ORIENTED SILICON STEEL: ON THE ORIGIN OF GOSS {110}<001> GRAINS I. Samajdar, S. Cicale*, B. Verlinden, P. Van Houtte and G. Abbruzzesse* Department MTM, Katholieke Universiteit Leuven, de Croylaan 2, 3001 Heverlee, Belgium *Centro Sviluppo Materiali, Viale Brin 218, 05100 Terni, Italy (Received June 2, 1998) (Accepted in revised form July 3, 1998) Background In grain oriented silicon steel suitable thermo-mechanical processing (e.g. hot rolling f cold rolling f primary recrystallization f secondary recrystallization) is needed to implement a strict texture control (1). The aim of such processing is to obtain a very strong Goss {110}001 texture. The final processed material typically contains very large Goss grains of the order of several cm with misori- entations 3 to 5° from the ideal Goss orientation. Evidently, the origin of such massive Goss grains exists in the primary recrystallized microstructure (1,2). Although considerable scientific efforts (3–9) have been directed to a better understanding of the secondary recrystallization and the ‘selection’ of precise Goss grains, our understanding on the primary recrystallization itself remains far from complete (1,10,11). Perhaps the most important issue in primary recrystallization is to identify and characterize the possible nucleation sources. Single and polycrystal studies have shown that Goss grains nucleate from microscopic shear bands, inclined respectively at  35° and  17° with the rolling direction (10,11). Ushioda and Hutchinson have observed (11) that the  35° shear bands are somewhat wider and recrystallized grains from such bands have a narrower spread (10° around the transverse direction (TD)) around exact Goss orientation, while relatively thinner  17° shear bands form recrystallized grains with a wider spread around the exact Goss component. Goss grains form preferentially from such shear bands - recrystallization from  35° bands being preferred over  17° bands (11). However, these classical observations (11) were made in a rolled F {111}112 oriented single crystal and need to be verified in a real polycrystalline material. In the present study, cold rolled grain oriented Si-steel with 70 and 90% reductions was given different annealing treatments in a laboratory salt bath, the annealing conditions being selected to avoid post-recrystallization grain growth. The evolution of Goss grains was observed at different stages of recrystallization, while an effort was made to relate them with the as deformed (but recovered) microstructures. Pergamon Scripta Materialia, Vol. 39, No. 8, pp. 1083-1088, 1998 Elsevier Science Ltd Copyright © 1998 Acta Metallurgica Inc. Printed in the USA. All rights reserved. 1359-6462/98 $19.00 + .00 PII S1359-6462(98)00288-7 1083