Method and tool for folding a metal strip

摘要

A method for folding a metal strip is proposed, the method comprising the steps of providing a metal strip (70) having a first surface and a second surface; providing the metal strip with a groove (62,62') in the first surface; folding the metal strip into a corner wherein the first surface forms a concave side of the corner and the second surface forms a convex side of the corner and the groove extends along the concave side of the corner; the metal strip being folded by means of at least one set of rollers. According to an important aspect of the invention, one of the rollers comprises a bead pressing the groove into said metal strip, the bead having a substantially rounded profile. The invention further concerns a folded tube having a groove with substantially rounded profile and a forming tool having a bead with substantially rounded profile.