Two-step annealing treatment for grain refinement of cold-worked AISI 316L stainless steel

Two-step annealing after cold rolling is proposed for the optimization of the annealing process of AISI 316L austenitic stainless steel toward more intense grain refinement. It was revealed that the first step of the annealing process at lower temperatures (i.e. 750 degrees C) can be used for the reversion of strain-induced martensite to austenite without uninhibited grain growth and recrystallization of the retained austenite. Afterwards, the primary recrystallization of the retained austenite takes place in the second step of the annealing process at higher temperatures (in the range of 850 to 950 degrees C). Carefully controlling the second annealing step resulted in a finer grain size and better mechanical response compared to those of a conventional one-step annealing approach.