2018 Volume 49 Issue 2 Pages 504-509
TRIP（TRansformation-Induced Plasticity） steels has excellent combination of strength and ductility due to the higher strain hardening properties. There are many researches on the deformation behavior and ductility of TRIP steels by tensile tests. However, the characteristics in a biaxial deformation which is the main body in actual press forming are not well known. For the application of the TRIP high strength steels to automotive structures, it is necessary to understand the forming behavior in various deformation modes, including plane stress and biaxial mode. In this study, forming limit diagram of 1180MPa grade TRIP steels are investigated with comparison of Dual-Phase steels of 590MPa and 1180MPa grade. As a result, it showed high dispensability of strain in all deformation modes and showed a stretch formability was equivalent to that of 590 MPa grade steel.
