SIMULATED HOT-WORKING, COLD-WORKING, AND ANNEALING OF AL-CONTAINING STEELS

An investigation was carried out on the effects of changing the hot-working, cold-working, and annealing parameters on the interaction between AlN precipitation and recrystallization in low-carbon steels containing significant amounts of Al and N. The primary aim was to determine whether laboratory torsion testing can be helpful in analyzing precipitation behavior in these steels. The approach taken was first to establish the baseline annealing behavior of material that was hot- and cold-worked in a mill and then to compare this with the behavior of material in which the hot and cold working were simulated by torsion testing. It was found, first of all, that torsion testing can indeed provide a good simulation of the industrial process of hot and cold working followed by annealing, even to the extent that a process as subtle as the inhibition of recrystallization by AlN precipitation can be accurately reproduced. The results also show that the interaction between precipitation and recrystallization during annealing is significantly influenced by the reheat temperature before hot working, as well as by the cooling rate after hot working.