Engineering, Energy, Transport AIC

Kateryna CHMYKH – Postgraduate Student of the Vinnytsia National Agrarian University (Sunny str., 3, Vinnytsia, Ukraine, 21008, e-mail: catherina099@gmail.com, https://orcid.org/0000-0001-8873-4436).

The article presents the results of a comprehensive study of forward slip during hot rolling of the wrought aluminum alloy AK6. Forward slip, defined as the difference between the circumferential speed of the rolls and the actual exit velocity of the metal from the deformation zone, is a key kinematic parameter that determines the accuracy of calculating the elongation zone length and ensures proper synchronization of successive passes in the technological process. Even a minor error in estimating this value may lead to the accumulation of geometric deviations, malfunction of the roll grooves, and defects at subsequent processing stages.
The aim of the study is to determine the regularities of forward slip variation depending on the rolling temperature conditions, degree of deformation, billet geometry, and roll-heating temperature. A series of experiments was carried out using AK6 alloy billets with diameters of 14–25 mm under reductions of 30, 40, and 50 % in smooth rolls with controlled temperature. The billets were heated to 450 °C, while the roll temperature varied from 20 to 450 °C. During rolling, forward slip was recorded and compared with the well-known analytical models of Pavlov, Fink, Ekelund, and Dresden–Golovin.
The results show that forward slip increases with higher reductions due to greater elongation and redistribution of velocities in the near-surface layers. Increasing both billet and roll temperatures reduces the friction coefficient, enhances metal plasticity, and intensifies dynamic recovery and recrystallization processes, which leads to increased forward slip. It was established that within the temperature range of 200–350 °C, at constant reduction, the influence of roll heating is minimal and forward slip changes only slightly. However, further heating to 450 °C results in a significant increase in the parameter – up to 47 %, depending on the deformation level.
The obtained dependencies make it possible to evaluate the influence of key technological parameters on the kinematic behavior of AK6 alloy and improve the accuracy of predicting geometric characteristics during hot rolling. The results can be applied to the optimization of reduction schedules, thermal preparation of billets and rolls, as well as to analytical and numerical deformation models for aluminum alloys.

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