Abstract: A flange for connecting piping is disclosed which comprises a ring form which can be welded along its inner edge to a pipe, and a flange ring. The ring form and the flange ring are both preferably of U-shaped cross section. The flange ring has holes for the insertion of clamping bolts and, when the flange connection is tightened, contacts an outer rim of the ring form. The inner rim of the flange ring has a height which is greater by a predetermined length than the height of the outer rim of the ring form. The predetermined length is selected so that when the clamping bolts are tightened, the flanged or base portion of the flange ring contacts the outer rim of the ring form after elastic re-shaping of the flange ring has taken place.