National University of Science and Technology “Moscow Institute of Steel and Alloys” (MISiS) (Moscow, Russia):

Kochanov A. V., Student, vasilich-K89@mail.ru
Gorbatyuk S. M., Dr. Eng., Head of a Chair

The analysis of the main methods of repair and restoration of forming rolls was carried out and its disadvantages were identified. It is shown that rolls operation during rolling is connected with large contact stresses, therefore high strength, wear resistance and durability  of rolls have great effect on mill productivity and product quality. Several methods can be used for surface strengthening of rolling rolls: volumetric quenching, surface quenching via induction heating by high-frequency current, roll surface processing by compressed scanned direct action arc in argon atmosphere and surface plastic deformation. Based on it one of the methods of surface plastic deformation was suggested for forming roll strengthening — it is rolling with hard-alloyed rolls, which then easier and faster for forming roll to restore its operational properties compared to thermal methods. The typical construction of device for strengthening of cold-rolling mill rolls with diameter from 193 to 265 mm was designed. Technological regime of strengthening was worked out, specified, energy-power and speed parameters, providing a high quality of the roll’s surface and cold-hardened layer depth. The main advantage of this technology is substantial simplification of roll repair and decrease of strengthening duration by 3 times. Usage of this method instead of conventional requenching allows to cut material expenses for restoration of one roll by 11%. It is planned in the future to conduct mathematical simulation of the process of strengthening of rolling rolls via proposed me thod in order to determine more exactly the depth of cold-worked layer taking into account all technological parameters and also to modernize the equipment to expand the range of diameters of processed rolls.

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