The Effect of Hot-Band Structure on Texture Development in Low-Carbon Steel Sheet

Low-carbon rimming steel has been hot rolled from 25 mm-thick slab to 2·5 mm sheet under conditions which simulated, as far as was possible in the laboratory, full-scale practice. After hot rolling, the strip was spray-cooled to a temperature corresponding to the coiling temperature and thereafter slowly cooled. Microstructures and textures were characterized at this stage. A standard cold-rolling and annealing treatment was given before the measurement of R values. Within a certain range of hot-finishing temperatures and spray-cooling temperatures, high R values (∼1·7) were developed. Comparisons were made with a steel of similar composition commercially hot rolled to 2·5 mm and then subjected to the same cold rolling and annealing treatment. The laboratory and commercial hot-rolled steels showed quite different grain-growth characteristics, which could not be attributed to differences in the average grain size or texture at the hotband stage. Subtle microstructural differences at this stage are thought to account for the differences in recrystallization behaviour, possibly involving an influence of carbide particles on grain-boundary migration rates.