Volgograd State Technical University, Volgograd, Russia
V. F. Petrova, Cand. Eng., Associate Prof., Dept. of Materials Technology, e-mail: tecmat@vstu.ru
V. N. Tsutskiridze, Student, Dept. of Materials Technology

The paper considers the effect of the degree of hot deformation on the microstructure of austenitic stainless steel. The hardness of the forged work piece is higher than that of the hotrolled one, which causes difficulties when processing it by cutting. The tendency of the austenite grain to increase from the surface of the work piece to the center in forged (degree of deformation 45 %) and hot-rolled work piece (degree of deformation 13 %) was revealed. The results of the microstructure study showed the presence of a carbide mesh along the boundaries of austenitic grains in a forged work piece. In a hot-rolled billet, carbides are located in the grain body and along the boundaries, but do not form a grid. During the study of the microstructure of the forged billet, heterogeneity and the presence of a polygonized structure in large deformed grains were found, which indicates the incompleteness of the recrystallization processes. The problems encountered during the subsequent cutting of the forged workpiece may be related to incomplete recrystallization processes and the unfavorable location of the carbide phase in the form of a grid. To eliminate these problems, a heat treatment - normalization process was proposed, which was carried out on model samples at a temperature of 950 °C and an exposure time of 1 hour, which allowed the processes of recrystallization of austenite to fully undergo, and led to the grinding of the structure. This intermediate heat treatment has led to a decrease in hardness, which will facilitate the cutting of the forged workpiece.

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