Determination of critical temperatures (Tnr, Ar3, Ar1) in hot rolling of structural steels with different Ti and N contents

Abstract

The simulation method applied to determine no-recrystallization temperature (Tnr) has also been used to simultaneously determine phase transformation temperatures on cooling (Ar3, Ar1) in a set of six steels with different Ti and N contents. A study has been made of the influence of Ti and N contents on these parameters for different strain conditions, and the results permit an estimation of what would be the most appropriate contents depending on the type of rolling (hot strip mill, near net shape casting). Austenite grain size was also determined at 1 100 °C and 1 300 °C for all the steels, it being found that a Ti/N ratio close to two gave the finest grain.