“JCOE” CALCULATION OF GEOMETRIC PARAMETERS OF PIPE BILLET’S EDGES BY SINGLE-RADIAL SCHEMES

Abstract

Methods for calculating the geometrical parameters of edge of the billet and the profile of the deforming tool are proposed for the process of forming welded large-diameter longitudinal pipes on the TESA 1420 line. A comparative analysis of geometry of the edge at the hem on the edge press was performed using the working surfaces of the tool, made by involute and single-radial schemes. Single-radial scheme allows to get the edge geometry that meets the technical requirements. For the section of an edge press the calculation procedure is presented, which allows to calculate the geometrical parameters of the edge during loading and unloading. Height of the bent edge, the residual radii of curvature, coordinates of the points of loading and unloading of outer and inner contours of the pipe billet edge have been defined. The involute profile of the tool is universal when changing one pipe size to another from a unifying pipe group. Further, in the calculations, a transition was made from profile of edge contour obtained by involute to the profile obtained by the multi-radial scheme, after which the fixed coordinates of the billet’s points were determined after unspringing. From the obtained coordinates, the output geometric parameters of the edge were estimated. For the unification group of 1220 – 1420 mm the longitudinal deformations of the edge for the size 1220×10 mm have been calculated and it was shown that the unification principles are much easier to implement with a single-radial profile of the tool. A technique for calculating the parameters of the edge of a pipe billet was developed and tested in the field of edge-bending presses using an instrument with a contact profile of a tool made by an involute. A one-dimensional calibration of the profile of an edge-bending tool is proposed, which provides fixed coordinates of the edge, similar to the coordinates for the involute profile of the punch. The calculated value of the weighted average radius of billet’s curvature ensures maximum approximation of the profile coordinates of the billet at fixed points for both calibrations (maximum divergence of coordinates according to the proposed schemes does not exceed 6 – 7 %). edge;