Методика визначення кінематичних параметрів поздовжнього прокатування у калібрах
Problems of accurate determination of the rolling radius Rkat in plugless longitudinal rolling of pipes are very important, because the accuracy of this factor determines the calculations of the speed of the continuous mill and, thus, affects the accuracy and quality of finished products. In order t...
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| Date: | 2023 |
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| Main Author: | |
| Format: | Article |
| Language: | Ukrainian |
| Published: |
Physico-technological Institute of Metals and Alloys
2023
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| Subjects: | |
| Online Access: | https://www.metalsandcasting.com/index.php/mcu/article/view/124 |
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| Journal Title: | Metal and Casting of Ukraine |
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Metal and Casting of Ukraine| Summary: | Problems of accurate determination of the rolling radius Rkat in plugless longitudinal rolling of pipes are very important, because the accuracy of this factor determines the calculations of the speed of the continuous mill and, thus, affects the accuracy and quality of finished products. In order to determine the size of the rolling radius Rkat the analytical techniques are being used, the essence of which depends on the assumptions about the nature of the physical processes that occur during rolling. In particular, this concerns the size and shape of the contact surface areas where the contact friction forces t are directed towards the rolling axis (lag area) and against it (the advance zone) and the position of the neutral line that separates these zones within the deformation zone. The existing methods for calculating the rolling radius Rkat use the assumption that the shape of the sections of the lag zone and advance zone can be assumed to be rectangular, and the neutral line is parallel to the axis of rolling. In this article a generalized technique is developed for calculating the rolling radius Rkat based on the analysis of the real shape of the neutral line in the deformation zone under the condition of the force equilibrium of the workpiece under the action of forces applied to it. It has been found that there can be four characteristic positions of the neutral line within the contact surface between the roll and the workpiece. A special case of a generalized technique is considered, in which the neutral line lies in a plane parallel to the rolling axis, and the calculated rolling radius Rkat of the roll is conditional. Values of the real Rkat and conditional Rkaty rolling radiuses under conditions of rolling tubes without mandrel in oval caliber were calculated and compared. An approximate dependence was obtained to adjust the calculated values of the conditional rolling radius. The results of the study were used to calculate the speed modes of rolling in the industrial calibration and reduction mills. Industrial tests have proven the fact of improving the accuracy of the wall and reducing the ovality of pipes produced using new speed modes during rolling. |
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