2019 Volume 68 Issue 5 Pages 116-119
Application of the high strength steel sheet to complicated forming parts has been studied as the weight of automobiles is reduced. Complex strain after forming may affect delayed fracture. Therefore, in this research, we devised a new delayed fracture evaluation method using a forming prediction technology, a forming limit diagram. Forming limit diagram was prepared and stress and hydrogen were applied to each forming mode （single axis, plane strain, biaxial strain）, and crack generation was evaluated. From the results of this study, it was found that the delayed fracture can be evaluated by the method using the forming limit diagram.
