Investigation into secondary phases in steels microalloyed with vanadium and nitrogen

Abstract

In the present work two nitrogen and vanadium microalloyed steels were compared in terms of the nitride or carbonitride phases present. The thermal evolved gas analysis clearly showed that one of the steels contains a higher volume fraction of nitrogen bound as vanadium carbonitride than the other steel in a natural relation to the total nitrogen content in steels. For the promotion of this statement, the content of free nitrogen with the use of the hot hydrogen extraction method was analysed and the thermodynamic prediction of the equilibrium composition of precipitating phases in microalloyed steels by the CALPHAD method with the use of the Thermo-Calc software was carried out.