Investigation of the character of change of geometrical dimensions of a tubular billet at its deformation by rolling method

Abstract

Obtaining bent pipe bends is an urgent scientific and technical task, for the solution of which it is necessary to determine the influence of the deformation process on the geometric dimensions of the billet. It is especially important to control the thinning of the outer wall of the bend, as this parameter is critical for the service characteristics of the bend. At the Department of Machine Building Technologies, Machine Tools and Instruments of South Ural State University (National Research University) works on studying the process of deformation of a tubular billet by the method of rolling with high tension are carried out. The article covers the influence of this deformation method on the wall thickness of the deformed billet, presents data on the character of wall thickness of a tubular billet when it is deformed by the method of rolling with high tension. The data on wall thickness change were obtained in two ways: computer modeling and measurements of experimental deformed pipe billet were carried out. Modeling was carried out using the software package MSC.Mars. The physical experiment on deformation of the tube billet was carried out on the laboratory installation for obtaining the experimental bent branch by the method of rolling with high tension. For the research work, a welded tube billet made of St2 steel, 57 mm in diameter and 4 mm wall thickness was used. In the course of modeling, calculated data on wall thickness change as a result of deformation into a tube bent branch were obtained. The wall thickness of the experimental bend was measured with an ultrasonic thickness gauge. Comparison of experi-mental data and modeling data showed a data discrepancy of 5–8 %. Such a discrepancy indicates the possibility of using computer modeling to predict the thinning of the outer wall in the process of deformation of pipe bends by rolling with high tension.