Determination of Rational Technological Parameters of Cold Bending with Rolling of Pipes from Corrosion-Resistant Steels

Abstract

The article describes the technology of cold bending of pipes with rolling from corrosion-resistant steels. It is shown that there are certain features arising in the process of cold bending of pipes made of corrosion-resistant steels, associated with their physical and mechanical properties. At the same time, due to a higher plasticity of these steels, an increase in the internal diameter of the pipe occurs during bending with rolling, which leads to a decrease in the actual tension, as a result, corrugations may appear on the inner surface of the pipe. In this regard, the assessment of the values of tension is made from the condition of the absence of corrugated pipes. In addition, the values of tensions were clarified on the basis of a number of restrictions, namely the shape and size of the deforming elements of the distributor, the limiting values of the pipe material elongations, ensuring the accuracy of the pipe shape in longitudinal section, and also taking into account the allowance for the internal diameter of the pipe. Based on the above, the values of rational tension and feed rates for bending pipes with a diameter of 57 mm with a wall thickness of 5 mm from steel grade 12X18H10T were determined. The results of theoretical calculations are verified by field experiments on a special machine. The results of the research will improve the accuracy of curved pipeline elements made of corrosion-resistant steels.