Analysis of edge crack behavior of steel sheet in multi-pass cold rolling based on a shear modified GTN damage model

• Shear modified GTN damage model is implemented.
• Shear damage parameter is identified via a special designed shear test.
• Influence of edge defects shape and size on the onset of edge cracks is investigated.

Edge cracks are commonly observed in steel strip in cold rolling, which may cause deterioration of quality and productivity of products. The edge defect is one of the important factors that lead to edge cracks in cold rolling. In this paper, the GTN damage model coupled with shear damage mechanism proposed by Nahshon and Hutchinson (2008) was employed to analyze the ductile damage and failure behavior of steel sheet with edge defects under multi-pass cold rolling. Cold rolling experiments of silicon steel with edge notches were performed on an experimental rolling mill to verify the accuracy of the numerical results. The simulation results show that two cracks appeared in the notch tip after five passes rolling and extended toward the direction with an angle around 45° and 135° to the rolling direction, which was in good agreement with the experimental data. The influences of notch shape and size on the onset of cracks around the notch tip are investigated and some significant conclusions are drawn.