Papers by Keyword: Deformation-Induced Ferrite Transformation

Abstract: Two mild steels with Nb-microalloying and Nb-free were smelted. After single-pass hot compression of various processes conducted on a Gleeble-2000 thermomechanical simulator, the effects of deformation conditions and Nb-microalloying on microstructural evolution kinetics, including the volume fraction, grain size and grain number per unit area were investigated through quantitative metallographic analysis. The experimental results show that, grain number per unit area of DIF increases with decreasing deformation temperature or increasing deformation amount; the grain size of DIF is not very sensitive to the deformation conditions; the volume fraction of DIF increases due to the increased grain number per unit area. The microalloying element of Nb dissolved in austenite inhibits the grain growth and reduces the volume fraction of DIF.

Abstract: Deformation Induced Ferrite Transformation (DIFT), i.e. transformation occurs during deformation applied in the temperatures above Ar3, has received wider attention since it has been proved to be a very effective way to produce ultrafine grained ferrite in low carbon steels. Although numerous works have been done on this topic in the past decade, the systematic works on DIFT in microalloyed steel, especially on the role of microalloying elements are still lacking compared with those in plain carbon steel. In this paper, the common features of DIFT will reviewed firstly, then an attempt will be made to elucidate the role of microalloying elements (niobium and vanadium) in DIFT, and the application of DIFT technology in microalloyed steels will be presented finally.