Evaluation of Microstructural Transformations in 201L Stainless Steel During Advanced Thermomechanical Process

In this study, microstructural transformations in AISI 201L stainless steel during advanced thermomechanical process is investigated. The as-cast specimens were first homogenized at 1200 °C for 15 h, and then hot forged in order to prepare a suitable microstructure for the subsequent treatment involving conventional cold rolling and annealing. Cold rolling was carried out at reductions of %10-95. The reversion of martensite to austenite in the cold rolled specimens was carried out by annealing in the temperature range of 750-900 °C for different times from 15 to 1800 s. The specimen microstructures were observed by optical and scanning electron microscopy (SEM). The identification of different phases was carried out using X-ray diffraction (XRD) and Feritscope. The results showed that increasing the strain resulted in an increased volume fraction of the strain induced martensite during cold rolling and a reduced martensite saturating strain. Also, the nanocrystalline austenitic structure with an average grain size of about 100 nm was obtained by annealing the %95 cold rolled specimen at 850 and 900 ºC for 30 s.