Evaluation Method for Delayed Fracture of Steel Sheet by V-Bending

Abstract

Delayed fracture property is one of the most important problem for the application of high strength steel sheet to the automotive parts. Conventionally, U-bending specimen has been commonly used for the evaluation of delayed fracture. However, the results, such as time to fracture, of U-bending specimen tends to fluctuate, and there is a possibility that the deformation state does not correspond to press formed automotive parts. In this report, V-bending specimen is proposed for the delayed fracture test. FE-simulation of U- and V-bending showed that V-bending is expected to accurately evaluate the delayed fracture properties of actual automotive parts.