Grain coarsening in IF steel during strain annealing

A study has been made of the grain growth in IF steel during strain annealing. A 92.5% cold rolled and annealed IF steel sheet was temper rolled by 0.4% and subsequently annealed at 750, 850, and 950 °C for various time periods. The grains started to grow abnormally near the surface and grew into the center during strain annealing. The pole figure and EBSD measurements showed that the abnormally grown grains did not have any orientation relation with the primary recrystallization texture. The calculated Taylor factors indicate that grains which underwent less deformation during temper rolling due to their orientations grow at the expense of surrounding grains. A major grain growth mechanism was regarded to be the strain induced grain boundary migration rather than grain boundary characteristics.