Theoretical Analysis Of The Rolling Process Of A Thick-Walled Thimble In An Elongating Mill

The technological process of rolling of seamless tube consists of three stages. In the first of them, a thimble shaped hollow is produced from the cast ingot (usually square), which in the second stage is rolled into the thimble. The next part of the manufacturing process is the main rolling on the mandrel, where intensive elongation is associated with the reduction of the cross-section. The last stage is the reduction rolling or calibration rolling in which the tubular thimble is shaped into a hot rolled tube.During research carried out in industrial conditions by the researchers of the Institute of Metal Forming and Safety Engineering of the Czestochowa University of Technology, aimed at increasing the efficiency of the tube rolling process in a pilgrim mill, the influence of the technological parameters of rolling on the quality of finished tube and the reduction of technological waste was found. The documentation and analysis recording data have shown that there is a possibility of multi-component adjustment of the extension mill settings affecting the flow behavior in the rolling gap. Proper selection of parameters will allow to control the metal flow behavior of the rolling thimble in a way which improves the quality of tubes manufactured by the pilgrim method.The paper presents preliminary results of numerical tests on the influence of the rolling process of a thimble in an elongation rolling mill on the material flow. Numerical modeling was carried out using the FORGE 2.1 NxT computer program. Based on results of computer simulations, the distribution of strain intensity and intensity of strain rate was determined. Based on the theoretical tests, it was found that it is possible to select the appropriate technological parameters to ensure a more even flow of material in the rolling gap and to improve the shape of the thimble after being rolled in the extension mill.