| Title |
Effects of Bainitic Transformation Temperature and Stress State on the Formability of C-Mn-Si TRIP Steel |
| Authors |
오진후(J . H . Oh),전현조(H . J . Jun),홍승갑(S . G . Hong),박찬경(C . G . Park) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
The effects of TRansformation Induced Plasticity(TRIP) phenomena on the plastic deformation of 0.2C-1.5Si-1.5Mn multiphase steel have been investigated at various heat treatment and stress conditions. In order to estimate a deformation behavior under multi-axial stress rotate, the hole expansion(HE) tests were carried out. It is shown that the formability evaluation from the uni-axial tensile tests was quite different from the formability measured from multi-axial HE-tests because of different stress state. The formability in the multi-axial stress state decreased due to the extinction of the transformable retained austenite at relatively earlier deformation stage and the production of irregular α` martensite. The voids of TRIP steel were initiated exactly at the interface between transformed martensite and ferrite matrix regardless of stress state. In addition, new form of experimental formula is proposed in order to predict the multi-axial formability of the TRIP steel from the results of uniaxial tensile test. |