PRECIPITATION SIMULATION AND X-RAY ABSORPTION SPECTROSCOPY FOR HOT ROLLED V-HSLA STEEL

Abstract

Aiming to the process optimisation while reducing or avoiding experimental work, the work has been carried out by a physically-based thermokinetic model proven by synchrotron X-ray absorption spectroscopy. The mole fraction and size distribution of different precipitate species as well as the consumption of the dissolved elements are of the main interest. The model considers the involved parameters in the hot rolling process, i.e., austenite grain size, disloca-tion density as a function of deformation, and thermal history during the process. Both grain boundary and dislocation are nucleation sites. The diffuse interface effect on the interfacial energy as well as a volumetric misfit of AlN at dislocations is also taken into account. The latter is because of its significant difference in the lattice parameter from the matrix. The X-Ray absorption spectroscopy (XAS) taken advantage from the synchrotron technology has been employed for the quantification of the precipitation of vanadium as well as its fraction in the solid solution. With very good agreement, V(C,N) precipitates significantly due to high dislocation and is not overridden by the competing AlN.