Effects of cold rolling and annealing on the ridging behaviour of ferritic stainless steel

A systematic study was carried out to evaluate the effects of cold rolling and annealing processes on the ridging severity of ferritic stainless steel (FSS). Both microstructural refinement and texture optimisation were achieved with an optimised processing schedule to improve the ridging resistance of FSS. Coarse grain bands comprising of primarily {112} <110> oriented grains were found to form inside cold-rolled and annealed FSS sheets. The effects of annealing schedules and the resultant microstructure and texture on the ridging behaviour of FSS are discussed. The results indicate that the reduction in the fraction of {001} <110> orientation by optimisation of the rolling processes contributes to reduce the ridging height of the FSS during the subsequent forming process. Through extending soaking time and under 880 °C during final annealing step, a maximum of 30% reduction in ridging height can be achieved with a refined microstructure and texture of FSS, improving the surface quality of FSS during subsequent forming processes.