Evolution of microstructure and crystallographic texture during recrystallisation of high-strength sheet steel

Abstract

Ultra-low carbon steels possess an attractive combination of mechanical properties namely drawability and strength that is suitable for automotive applications. A high-strength variant of the material containing large amounts of manganese and phosphorous has been produced in the laboratory. The main objective of the present work was to study the microstructural evolution after recrystallisation, below and above the critical phase transformation temperatures of the steel. Crystallographic texture of ferrite was found to intensify with increasing the annealing temperature; surprisingly even beyond the upper transformation temperature. The texture measurement data obtained with the electron backscatter diffraction and X-ray diffraction matched very well with each other. The steel recorded an impressive strength–drawability balance mainly due to solid solution strengthening and favourable γ-fibre texture.