Nosov Magnitogorsk State Technical University, Magnitogorsk, Russia:

N. A. Feoktistov, Cand. Eng., Associate Prof., Head of the Dept. of Foundry Processes and Materials Science, e-mail: fna87@mail.ru

The article presents results of the research aimed at studying the processes of roll steel grade 150KhNM structure formation while manufacturing products from it, as well as the influence of the chemical composition on the level of mechanical and operational properties. The introduction providesa brief overview of the studied steel for mill rolls. The article considers technological peculiarities of building mill rolls from hypereutectoid steel, as well as processes of forming cast structure and its interaction with mechanical and operational properties. The methodical part of the article provides materials and methods of the research, as well as considers the equipment that was used for the experimental work. The research part of the article presents the results of the work done, as well as their description. The processes of structure formation during the primary and secondary crystallization are considered, the influence of thermal conditions of melting crystallization on these processes, as well as the properties of the resulting product are estimated. The article pays special attention to the influence of nitrated ferrochromium on the structure and properties of roll steel. The method of thermal analysis shows the differences in the processes under heat treatment, as well as the temperature intervals of dissolution carbide phase, decarbonization during the steel heating process. In addition, the complex influence of nitrogen and chromium on the hardness and durability of roll steel has been studied, and recommendations on application of this material in industrial conditions have been given. In conclusion the article summarizes the received materials and results, as well as estimates possibility of nitrogenous ferrochromium application in the roll mill production conditions.

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