Moscow Polytechnic University (Moscow, Russia):

R. L. Shatalov, Dr. Eng., Prof., Dept. of Metal Forming and Additive Technologies, e-mail: mmomd@mail.ru
S. A. Tipalin, Cand Eng., Associate Prof., Dept. of Metal Forming and Additive Technologies, e-mail: tsa-mami@mail.ru
V. A. Medvedev, Graduate Student., Dept. of Metal Forming and Additive Technologies, e-mail: 10-bmt@mail.ru

The formation of a decarburized layer and the hardness of vessels made of steel 50 were studied during hot forging after hot screw rolling on the floor of a discontinuous production line of the NPO Pribor plant. It is shown that after screw rolling, the ferrite layer on the surface of rough vessels is continuous and almost uniform in thickness and wall height. Subsequent processing of vessels in cases of hot stamping on a horizontal press revealed a significant inhomogeneous movement and mixing of ferrite along the depth and height of the deformed vessel. A study of Rockwell hardness and microstructure made it possible to establish quantitative patterns of the distribution of ferrite and its effect on the hardness of vascular sites. An analysis of the described data allowed us to find the relationship between the change in ferrite ring size and HRC hardness by constructing regression equations to determine the effect of its displacement on the strength characteristics of steel vessels during stamping on a rolling-press line.

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