Determination of no-recrystallisation temperature in Nb-V-Ti microalloyed steel and discussion of its definition

Abstract

Using torsion tests, the no-recrystallisation temperature T_nr was determined for two cooling rates in a Nb-V-Ti microalloyed steel. The same tests made it possible to deduce the A_r3 phase transformation temperature. When Tnr is known, it is possible to establish approximately the conditions for which the strip rolling or plate rolling of this steel must be performed to obtain the appropriate microstructure. With the aid of a recrystallisation model and the results obtained in other work, a discussion is made of the concept of Tnr the conclusion being that it represents the temperature above which the fraction recrystallised between consecutive passes reaches a value close to 50% and not 100%. This parameter, and the value of A_r3, can be determined at minimal cost and in a relatively short time. Both economic and time aspects are of interest to any steel manufacturer producing hot rolled microalloyed steels.