Tula State University (Tula, Russia):

V. B. Protasyev, Dr. Eng., Prof., e-mail: avprotasev@mail.ru
N. N. Batova, Cand. Eng., Associate Prof., e-mail: nolga06@mail.ru

The possibilities of cross-screw rolling in terms of productivity, fineness, quality of the outer surface and the absence of looseness of the metal in the axial zone of rolled billets are considered. It is shown that the traditional design of the rolls is not guaranteed to provide continuity of the metal and requires correction of deformation patterns and additional machining operations of the pole zones of the workpieces and the outer surface of the semi-finished products. The design of rolls using the method of breaking and uniform relative deformation of jumpers for the purpose of reduction in 2,5 times of the number of cycles necessary for the formation of billets of the «lentil» type is analyzed. As a result, the appearance of looseness in the axial zone of the blanks is guaranteed. Suitability of preparations for mass production of products with the increased requirements to quality of a surface at use of operations of cold extrusion and an extract is shown. The rolls are produced on special machines using milling at preliminary operations and grinding after quenching and when restoring working capacity by grinding, they provide not less than 1,200,000 pieces. The process is implemented in production and has been successfully used for more than 30 years.

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