TPT March 2010

Multi-roll straighteners for tubes

ASMAG, Austria, a supplier to the steel and non-ferrous metals industry, has developed a new multi-roll straightening machine for steel tubes for Wiederholt GmbH, Germany. The 10-roll-straightener – branded type RRM-pro 125/420/10 – works up to a maximum tube outside diameter of 125mm, at a line speed of 180m/min. To achieve the best accuracy in straightness, a new drive system was developed to reduce the roller centre distances to a minimum. The individual high efficiency AC servomotors enable roll wear compensation and high dynamic process control. A further feature of the machine is the identical design of the vertical and angular adjustment of all ten rollers. In association with additional adjustments on the inlet and outlet troughs, the first and fifth pairs of rollers can be fully integrated into the tube bending/ovalisation process. The centreline of the machine can be changed. The vertical adjustment of each roller is performed by hydraulic cylinders controlled by servo valves; each roller is limited in load by limiting the pressure in the hydraulic cylinder. Together with direct measuring by absolute encoders, clearances in the system are eliminated. With the new ‘Realtime Setting’ straightening mode, adjustments are not restricted to the time period before and after a cycle. This mode has already been proven on the ASMAG 2-roll-bar straightening machines, and allows adjustments during the straightening process in real time. The mode also enables different settings for tube rear end, front end and the remaining tube, if necessary. For this purpose the drives of the high dynamic controlled vertical and angular adjustments of the rollers are designed and calculated to suit challenging straightening loads. The straightening machine is part of a fully automatic drawing line for welded tubes, incorporating pointing, drawing, tube rear and front-end cutting, straightening, ultrasonic/eddy-current testing and multiple cutting equipment.

ASMAG GmbH – Austria Fax: +43 7616 8801 44 Email: sales@asmag.at Website: www.asmag.at

ASMAG’s straightening machine

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