Development of Texture, Microstructure, and Grain Boundary Character Distribution in a High-Strength Boron-Added Interstitial-Free Steel after Severe Cold Rolling and Annealing

Abstract

A high-strength boron-added interstitial-free (IF) steel was subjected to cold rolling by 90 and 98 pct. Both these materials were subjected to annealing at 650 °C and 700 °C for various lengths of time. An in-depth thorough study has been carried out on the evolution of texture, microstructure, and grain boundary character distribution (GBCD), as a function of cold rolling and annealing. Formation of strain-free nanosize grains at few places has been observed in the severely cold-rolled (98 pct) steel. Ultrafine grains formed in this material at the early stages of annealing. The deformation texture sharpened and the high-angle grain boundary (HAGB) density increased with increasing amount of cold rolling. The intensity of α-fiber components increased at the early stages of annealing, while the γ-fiber components were found to predominate at the later stages. Selective growth of grains having orientations {111}\( \langle 123\rangle \) and {554}\( \langle 225\rangle \) occurred in the 98 pct cold-rolled and annealed material. The textural and microstructural results indicate that in these materials the recrystallization process may be of a continuous type.