Abstract: The aim of the invention is to provide a method for controlling the flow of material when deep-drawing a workpiece, which better utilizes the drawing capacity of a workpiece and produces a better shape accuracy, particularly of the bottom of the drawn part. The aim is achieved by a method in which the deep-drawing process is performed incrementally and in which at least one bead is incorporated into the flange region of the workpiece prior to each increment of the deep-drawing process. Due to this, the shape accuracy of the bottom can be improved and material accumulations in the flange zone can be prevented.

Abstract: The aim of the invention is to provide a method for controlling the flow of material when deep-drawing a workpiece, which better utilizes the drawing capacity of a workpiece and produces a better shape accuracy, particularly of the bottom of the drawn part. The aim is achieved by a method in which the deep-drawing process is performed incrementally and in which at least one bead is incorporated into the flange region of the workpiece prior to each increment of the deep-drawing process. Due to this, the shape accuracy of the bottom can be improved and material accumulations in the flange zone can be prevented.

Abstract: The invention relates to a bending mandrel for a bending device and also to a bending method for pipes, more particularly pipes which have a large diameter-to-wall thickness ratio and are to be bent by a small radius, for example, of the order of magnitude of the pipe diameter. To this end use is made of a bending mandrel (5, 6) to whose rigid head (5) assembly (6) of springy sheet metal lamellae (6a, 6b) is attached to improve the bendability of the bending mandrel (5, 6) while maintaining a satisfactory supporting action, the lamellae (6a), with the exception of the outer lamellae (6b), having window-like cutaway portions (6c).

Abstract: The invention relates to a double-layered sheet metal with a first layer (5) of sheet metal comprising indented knobs (4.sub.I -4.sub.IV ; 4.sub.V -4.sub.VII ; 4.sub.VIII -4.sub.XIII), with several of these knobs forming the corner points of a geometrical segment (8.sub.I, 8.sub.II, 8.sub.III) of the first layer (5) of sheet metal, with a second layer (6) of sheet metal which is connected to the first layer (5) of sheet metal in the area of the tips (4a) of the knobs (4.sub.I -4.sub.IV ; 4.sub.V -4.sub.VII ; 4.sub.VIII -4.sub.XIII), and with a filling (7) made of filling material arranged in the void remaining between the layers (5, 6) of sheet metal. With such a double-layered sheet metal the danger of "total failure" in the case of a load exceeding elastically endured deformation is reduced in that the geometrical segment (8.sub.I, 8.sub.II, 8.sub.