INFLUENCE OF VANADIUM ON THE STATIC RECRYSTALLIZATION OF AUSTENITE INMICROALLOYED STEELS

Torsion tests were conducted to study the static recrystallization of three microalloyed steels manufactured by electroslag remelting (ESR) with different percentages of vanadium, 0.043%. 0.060% and 0.095%, res pectively, and approximately equal percentages of the other alloy-form ing elements. It was seen that, in contrast to niobium, dissolved vana dium has no influence on the activation energy. The influence only bec omes notable when the precipitates start to form and the activation en ergy increases rapidly, thus inhibiting recrystallization. The critica l temperature at which inhibition commences was measured as a function of the vanadium content and the deformation performed, and in all cas es it was lower than the dissolution temperature deduced from the solu bility products for nitrides, mainly because the testing conditions la cked thermodynamic equilibrium. Finally, a comparison was made of the microstructures obtained in two commercial steels, namely a C-Mn type steel and a vanadium microalloyed steel. Both were subjected to the sa me cycle of successive deformations, whose temperatures were lower tha n the critical temperature. After the last deformation, a much harder austenite was obtained in the microalloyed steel than in the C-Mn stee l.