Graebener has a rich legacy of building customised machines for use in pipe mills. The new pipe bending press is used for bending open-seam pipes and half-shells in a step bending process.
September 1, 2022
Germany-based Graebener Maschinentechnik GmbH & Co. KG is the top choice for a leading global manufacturer of longitudinally welded large-diameter pipes. With the new Graebener® Pipe Bending Press, the global player optimises its production processes and is able to manufacture an enormous range of the most diverse special pipes with a wide range of dimensions and extreme diameter-to-wall thickness ratios.
The machine manufacturer has been building customised machines for use in pipe mills for decades. The recently developed pipe bending press is used for bending open-seam pipes and half-shells in a step bending process. The special feature of this custom-built machine is its enormous flexibility, as it can be used to produce tubes of the most varied dimensions: with outside diameters from 12″ to 48″ (up to 100″ for half-shells), wall thicknesses from 12 to 75 mm, and lengths between 6 and 13.2 m.
Notably, the unique feature of the pipe bending press is that it can be utilised to produce tubes with very small diameters and high wall thicknesses. Materials with high yield strengths, such as X80, X90, and X100, can be processed seamlessly. For such an enormous production spectrum, large-diameter pipe manufacturers, several lines are normally needed.
Another plus point is the enlarged stroke of the bending sword as well as its stable lateral guidance. The enlarged stroke ensures that the sword can be completely pulled out of the tube after the completion of the bending process. This means that the remaining gap in the tube can be closed directly in the machine with the aid of the sword itself. The stable lateral guidance makes this process possible even for small, thick-walled tubes. Thus, an additional pipe closing press is thus no longer necessary. With the Graebener® Pipe Bending Press, investment volumes can be reduced and production cycles can be shortened.
The bending press has a press force of 70,000 kN, which is achieved by six controlled hydraulic cylinders on the bending sword. Thanks to a special force distribution and control system, even small, thick- walled tubes can be produced. For six-meter-long tubes, for example, the press achieves a press force of an exceptional 52,000 kN.
If tube diameters of up to 100″ are to be produced, the press can be used to bend half-shells which are later assembled into a tube. A specially developed handling system ensures the automated removal of the half-shells after the bending process. Simultaneously, all process parameters are stored with help of the Graebener® BendPro automation system, so that the settings and travel range for recurring products can be recalled at any time.
All Graebener® bending presses are designed in such a way that the various tube sizes in the standard dimension range can be produced flexibly and without changeover. The changeover time for dimension-dependent tools is eliminated and thus contributes to increasing the efficiency of the bending process.