Genetic Evolution of Inclusions in Interstitial-Free Steel During the Cold Rolling Processes

摘要

In present work, the genetic evolution behavior of inclusions in interstitial-Free steel sheets during the cold rolling processes have been investigated based on nano-indentation. The genetic evolution of inclusions in shape and position has been calculated by 2-D finite element model. The inclusions spread along the rolling direction and compress along the IF steel sheets thickness direction. The inclusion's profiles calculated by simulation are consistent with that obtained by experiments. After multi-pass cold rolling, the inclusions can be moved a short distance toward the sheet surface. When the Al2O3 and TiN sizes are less than 30 and 20 mu m, the displacements are approximately 6 and 10 mu m respectively. While the diameter of Al2O3 is 100 mu m, the maximum displacement is approximately 30 mu m. Both the Al2O3 and TiN in the position of 1/2 of the sheet have little displacements after multi-pass rolling. On the contrary, the inclusion located at 1/8th position of the sheet, the actual displacements are more than 30 mu m. The shorter the distance between the inclusion and the IF steel sheet surface, the larger the inclusion displaces. Furthermore, the relationship between inclusions and surface defects have also been discussed.