Abstract: A method for producing a tube with a bent progression or with a bend embodied as a transverse progression. For bending the tube or for each fold of the transverse progression, two miter cuts are made into an essentially straight tube, thus creating two tube sections with miter cut surfaces extending along the cutting planes and a cutting wedge. The miter cuts are placed such that the cutting planes intersect at a point located inside the tube wall, and at this point a bendable bar is left intact connecting the two tube sections. The miter cuts are made such that the cutting wedge first remains in the tube via not-severed or incompletely severed holding points for tube transport. The cutting wedge is then removed and the miter cut surfaces of the two tube sections are folded onto each other around the bar which acts as a hinge and then allows both tube sections to be welded together all around their miter cut surfaces.

Abstract: A method and preprocessed tube for producing a tube with a bent progression or bend embodied as a transverse progression. For the bent position of the tube or for each fold of the transverse progression, two miter cuts are made into an essentially straight tube, creating two tube sections with miter cut surfaces extending along cutting planes and a cutting wedge. The miter cuts are placed such that the cutting planes intersect at a point located inside the tube wall, and at this point a bendable bar is left intact connecting the two tube sections. A folding of the miter cut surfaces of the two tube sections onto each other around the bar acting as a hinge allows both tube sections to be welded together around their miter cut surfaces. An additional centering aid formed by a protrusion and a recess can be provided in the opposite miter cut surfaces.

Abstract: A method and a preprocessed tube for producing a tube with a bent progression or with a bend embodied as a transverse progression. For the bent position of the tube or for each fold of the transverse progression, two miter cuts are made into an essentially straight tube, thus creating two tube sections with miter cut surfaces extending along the cutting planes and a cutting wedge. The miter cuts are placed according to the invention such that the cutting planes intersect at a point located inside the tube wall, and at this point a bendable bar is left intact connecting the two tube sections. A folding of the miter cut surfaces of the two tube sections onto each other around the bar acting as a hinge then allows both tube sections to be welded together all around their miter cut surfaces. Preferably an additional centering aid in form of a protrusion and a form-fitting recess is provided in the two opposite miter cut surfaces.