Roller bending of edges of steel tubal billet. Part 1. Two-radius profile of rolls

Bending the sheet’s edges is a mandatory operation in the production of the single-seam welded steel pipes of large diameter. Usually, the operation of edges’ bending of a flat steel sheet foregoes the operation of pipe billet’s forming on the presses (for example, in the technology of the German company SMS Meer). However, when forming a pipe billet on the three-roller mills, the operation of edges’ bending of steel sheet is carried out after the roller operation of sheet (for example, in the technology of the Swiss company Haeusler). This is due to the fact that after forming the sheet on three-roller mills, the large non-deformable flat sections of the sheet (splines) remain at the edges of pipe billet, which do not allow for the high-quality gas assembly of the pipe billet’s edges. To solve this problem, the company Haeusler has developed the roller edge-bending mills, located after the three-roller mills by Haeusler. In this paper, the mathematical model for calculating the shape of the steel tubal billet’s edges, when the billet is formed on the roller edgebending mills by the company Haeusler with the two-radial surface profile of rollers, is constructed.