Method for producing open-seam pipes

A method for producing an open-seam pipe (1) from a flat metal product (2) with a bending tool (3) and at least one externally located lower tool (4), the method comprising:

• calculating, in advance, a plurality of positions of individual bending steps and an insertion depth of the bending tool (3);
• bending the flat metal product (2) step-by-step to form the open-seam pipe (1) based on the advance calculation by bringing together two longitudinal edges (6a, 6b) of the flat metal product (2);
• carrying out, after each of the individual bending steps, a target/actual comparison of a distance between the two longitudinal edges (6a, 6b) at at least one position arranged along a longitudinal extent of the flat metal product (2) and/or between one of the two longitudinal edges (6a) and an axial center line (7) of the flat metal product (2);
• and
• determining, in an event of a deviation, a correction value for a subsequent bending step using a correction algorithm and adapting the insertion depth for the bending tool (3),
• wherein at least one of the two longitudinal edges (6a, 6b) comprises at least three edge points (9a, 9b) on a basis of which the target/actual comparison of the distance is carried out, and
• wherein the at least three edge points (9a, 9b) are spaced apart across a thickness of the at least one of the two longitudinal edges (6a, 6b).