Effect of Hot-rolling Strain Rate in the Ferrite Region on the Re-crystallization Texture of Extra-low C Sheet Steels

Abstract

High strain-rate rolling in the ferrite region has been adopted to develop the {111} recrystallization texture in extra-low C steel without cold-rolling. The intensity of the {222} component in the recrystallized sheet steel can be increased by increasing the rolling strain rate. Conversely, the texture of hot-rolled sheet steel, which is similar to that of cold-rolled sheet steel, does not depend on the strain rate. The {222} residual strain in specimens rolled at a high strain-rate is significantly higher than that in the low strain-rate specimens, while the {211}, {200} and {110} residual strains are independent of the strain rate. High strain-rate rolling can lead to more rapid recovery of {222} residual strain during annealing. As a result, it is considered that high strain-rate rolling in the ferrite region provides high stored energy preferentially in the {111} component, with the result that the region of high stored energy in the {111} component recovers and nucleates swiftly and a strong {111} recrystallization texture is developed. Moreover, high strain-rate rolling of high-purity iron makes it possible to recrystallize the material quickly and obtain the high r-value associated with a {111} recrystallization texture without annealing as well as cold-rolling. © 1994, The Iron and Steel Institute of Japan. All rights reserved.