| Title |
Influence of Finish Rolling Temperature on Microstructure and Mechanical Properites of as - hot - rolled Dual Phase Steels |
| Authors |
홍승찬(Seung Chan Hong),강성룡(Seong Ryong Kang),이경섭(Kyung Sub Lee) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
In this study controlled rolling process was simulated to produce as hot rolled dual phase steel by using thermo-mechanical simulator(Gleeble 1500). Final microstructure and mechanical properties depending on finishing rolling temperature prior to intercritical heat treatment were investigated. In addition, austenite recrystallization behavior and γ/α transformation temperature of Nb containing steel were measured by various methods. The major results were as follows : the strength and elongation were improved as the finishing temperature decreased as low as 800℃ due to ferrite grain refinement by the increase of ferrite nucleation sites and acceleration of the γ/α transformation. When finishing rolling was performed at temperature below 800℃, however, the strength was decreased because of the increase of ferrite volume fraction. V and Nb were effective for retardation of austenite recrystallization so that nonrecrystallization region was extended. It was effective for ferrite refinement. Furthermore, it makes possible to perform finishing rolling at high temperature. During the intercritical heat treatment the coarsening of ferrite occurred. Repeating deformation just above Ar₃ temperature was effective for the suppression of ferrite coarsening. |