Quantitative Analysis of Three-Dimensional Lamellar Alignment in Pearlitic Steel With Various Pre-processing Using Semi-automatic Habit Plane Analysis

The three-dimensional lamellar alignment of pearlitic steels pre-processed with cold rolling and drawing before the pearlitic transformation was quantitatively evaluated using a semi-automatic habit plane analysis. The analysis was successfully conducted, although the habit planes were dispersed depending on the geometry of the specimen owing to the cementite (Fe3C) plates interrupting the incident electron beam to the ferrite (alpha) phase during the electron backscattered diffraction analysis. Pitsch-Petch and Isaichev orientation relationships between alpha and Fe3C were detected within one block. The block and colony sizes and lamellar spacing were insignificantly changed by pre-processing, however, the alpha phase texture was differed according to the pre-processing conditions. The rolling texture in the cold-rolled specimen inherited even after heat-treatment. The non-pre-processed specimen exhibited a random lamellar alignment distribution, whereas specific lamellar alignments were accumulated in the pre-processed specimens, strongly suggesting that pre-processing affected the lamellar alignment. The number of colonies in the pre-processed specimens with a lamellar alignment (normal of habit plane) perpendicular to the stress axis during pre-processing tended to be small. The lamellar alignment tended to fit that expected from the texture in pre-processed specimens. The texture and residual stress developed during pre-processing may affect the lamellar alignment in pearlitic steels.

Automated summary

The three-dimensional lamellar alignment of pearlitic steels pre-processed with cold rolling and drawing was evaluated. The pre-processing had a significant impact on the lamellar alignment, as specific alignments were accumulated in the pre-processed specimens. The size and spacing of the colonies and lamellae were not affected by pre-processing.