Expanded use of vanadium in new generations of high strength steels
The goal of this paper is to present a new role of vanadium on; (i) ferrite grain refinement through nucleation of intragranular ferrite, and (ii) precipitation strengthening of bainitic steels. Microalloying with vanadium is extensively used for strong and easy controllable precipitation strengthening of HSLA with ferrite-pearlite microstructures. The benefits of precipitation strengthening are now being extended on high strength bainitic steels. The experimental results clearly indicate an abundant precipitation of nanoscale nitrides and carbides in the dislocated bainitic ferrite matrix, over a broad temperature range down to 300°C. Vanadium can also by effectively use for ferrite grain refinement. It is shown in this paper that vanadium contributes to the formation of two types of intragranulary nucleated ferrite; polygonal ferrite and acicular ferrite. Intragranular polygonal ferrite nucleates on VN particles in austenite. Acicular ferrite forms during transformation at lower temperatures.
vanadium, grain refinement, intragranular polygonal, acicular ferrite, precipitation, strengthening, bainite
Corrosion and Metals Research Institute (KIMAB)
MS&T 2006: Proceedings from the Materials Science & Technology Conference, Cincinnati, Ohio, 15-19 October 2006