Avoiding Roping and Ridging in AA6XXX Sheets: Characterizing the Initial State

The roping and ridging phenomenon is investigated in samples of AA6XXX. Two classes of materials were compared namely, those exhibiting good (OR) and bad roping (BR) behaviours, respectively. The initial microstructures and microtextures were examined via electron back-scatter diffraction (EBSD) with an emphasis on grain size distributions, texture strength and spatial distribution of specific (texture) components. The grain size distributions of these materials were not significantly different with corresponding average (grain) diameters of 29 and 28 pm for the OR and BR materials, respectively. The overall texture strength is higher in the BR case compared to the OR sample, approximate to 7 MRD vs. 2.6 MRD. It was found that the {001} CH component occurred with the highest frequency in the OR material while grains having the {123} S orientation had the largest volume fraction in the BR case. Despite these observations however, the CH component appeared only mildly banded in the OR material while grains having the S orientation exhibited a more uniform spatial distribution in the BR sample. Partial bands of Cube-oriented grains were observed in the GR material; Cube bands extended fully along the rolling direction (RD) in the BR material. The Cube volume fractions differ by about 47%, with the BR material having the higher fraction compared to the OR case. The major difference between these two materials is the spatial distribution of the Cube texture component.