Vibrations in engineering and technology

Chmykh Kateryna – Recipient of the Third Educational and Scientific Level of the Vinnytsia National Agrarian University (Sunny str., 3, Vinnytsia, Ukraine, 21008, e-mail: catherina099@gmail.com, https://orcid.org/0000-0001-8873-4436). 

This article presents a comprehensive study of the transverse spreading (Δb) of the AK6 aluminum alloy during hot rolling, taking into account the influence of key technological parameters, structural transformations, and contact conditions between the metal and the rolls. The aim of the study is to determine the regularities of lateral metal flow, evaluate the roles of temperature, reduction degree, billet diameter, and roll diameter in forming the magnitude of Δb, as well as to assess the accuracy of analytical models used for predicting spreading under hot deformation conditions.

Experimental tests were conducted on billets of various diameters and at different reduction levels, enabling an analysis of the effects of geometric and kinematic factors on metal flow within the deformation zone. It is shown that hot rolling results in reduced transverse spreading compared to cold deformation due to lower flow stress, activation of dynamic recovery and recrystallization, and increased plasticity of the AK6 alloy within the temperature range of 420–480 °С. It was established that the reduction degree is a decisive factor governing the nonlinear growth of Δb, whereas an increase in the initial billet diameter leads to a decrease in lateral flow due to stronger transverse frictional forces and changes in the deformation zone geometry.

It is demonstrated that the roll diameter significantly affects spreading intensity: a larger roll diameter (D) increases the deformation zone length, intensifies tangential friction forces, and contributes to partial redistribution of metal flow in the transverse direction. Special attention is given to comparing analytical models by Passini, Skriabin, and temperature-corrected formulations, all of which showed satisfactory agreement with experimental findings. This confirms their suitability for engineering calculations and practical prediction of spreading under varying technological conditions.

The obtained results have important practical implications for optimizing hot rolling processes of aluminum alloys. They make it possible to reduce errors in roll pass design, improve the dimensional accuracy of rolled products, minimize the risk of edge defects (waviness, “earing”, microcracks), and ensure stable performance characteristics of AK6 alloy products.

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