Influence of thermo-plastic deformation on grain size of high-manganese austenitic X11MnSiAl17-3-1 steel

Purpose: The aim of the paper is to compare fragmentation of grains after thermo-mechanical treatment using Gleeble 3800 simulator of high-manganese austenitic X11MnSiAl7-1-3 steel. Design/methodology/approach: The hot-working behaviour was determined 4- and 8-stage compression tests performed in a temperature range of 850 to 1100°C by the use of the Gleeble 3800 thermo-mechanical simulator. The comparison between two type of thermo-mechanical treatment has been established based on microstructure research and X-ray diffraction analysis. Findings: It was found that steel X11MnSiAl7-1-3 in initial state and after thermo-mechanical treatment on Gleeble simulator has homogeneous austenite structure. Compression tests were realized in the temperature range from 850 to 1050°C with the true strain 4x0.23 for 4-stage process, and 0.4 in the first deformation, and 0.25 and 0.2 in the following deformations for 8-stage process. The multi-stage compression examination gives the possibility to refine the austenite microstructure. Based on microstructures research were found that this process perfectly led to fragmentation of the material structure which may result in the ideal material properties. Practical implications: The obtained microstructure after Gleeble simulations can be useful in determination of power-force parameters of hot-rolling for thin sheets to obtain fine-grained austenitic microstructures. Originality/value: The hot-working behaviour and microstructure evolution in various conditions of plastic deformation for new-developed high-manganese austenitic steels were investigated.