Evaluation of Intermediate Annealing on Nb-Stabilized Ferritic Stainless Steel

Abstract

This study seeks to evaluate the effect of intermediate annealing on the microstructure, texture, and formability of Nb-stabilized ferritic stainless steel. Two routes - direct cold rolling and cold rolling with an intermediate annealing were performed. The total reduction was 80%, 3-0.6 mm and 3-1.2-0.6 mm. The characterization of the samples was conducted using X-ray diffraction, electron backscatter diffraction, and tensile tests to evaluate the formability by the average normal anisotropy coefficient, r value. The results showed that intermediate annealing promoted the strongest γ-fiber with peak at {111}〈112〉 and weak α-fiber after cold rolling. After the final annealing, it was observed that intermediate annealing reduces the banded microstructure and θ-fiber, and improves the γ-fiber uniformity and the r value. It is worth noting that the γ-fiber fraction was the same for direct reduction. The increase in r value was related to the reduction in θ-fiber and the uniformity of texture recrystallization.

Keywords

• ferritic stainless steels
• intermediate annealing
• cold rolling
• texture