TPT March 2010

T echnology U pdate

Multi-channel tube measuring

extracting mill. In this way a large part of the tube is measured while it is still in the mill stand and it is ensured that all measurement results are assigned to the right angle positions. The first system with integrated outside diameter and profile measuring system is being used at Vallourec & Sumitomo Tubos do Brasil Ltd. IMS Messsysteme GmbH – Germany Fax: +49 205 69750 Website: www.ims-gmbh.de

EFFICIENT control of premium quality finishing (PQF) mills for the production of seamless tubes is inconceivable without suitable measuring systems: it no longer suffices to simply measure average values for wall thickness, eccentricity and diameter. On the contrary, local, high-resolution data and their assignment to length and angle position are of critical importance. The new multi-channel tube measuring system from IMS, which is installed at the exit of the extracting mill, measures wall thickness and outside diameter online and with high local resolution of the length and angle positions. It also measures the amplitudes and phase positions of eccentricities along the complete length of the tubes. Apart from the well-established radiometric 13-channel thickness measuring system, which is used for continuous measurement of wall thickness around the circumference of the tube, IMS has recently started offering to equip new systems with an optical diameter measuring system with 18 laser triangulation sensors. In this way IMS measures all the geometrical data necessary for optimum control of the rolling process in the upstream PQF mill and downstream stretch-reducing mill with a single gauge directly behind the extracting mill. The measured values are grouped according to various criteria and can be displayed both as “wall thickness carpet” and as pie chart for every single length segment. The values are sent to the automation system and used to control the PQF mill. In addition to the automated general adjustment of the rolls and control of the roll gap, it is now also possible to adjust the rolls dynamically during the rolling process. In this way it is firstly possible to compensate changes in the rolling parameters within a single rolling process, for example temperature influences. It is secondly possible to cause wall thickness changes quite deliberately. For example, it is possible to roll PQF tube ends with reduced wall thickness, thereby avoiding thickened ends in the stretch reducing mill. The measured values are also used for three crucial control functions in the stretch reducing mill, which would not be possible without measurement of the wall thickness and its local assignment: namely, for control of the tube ends to reduce losses at the tube end, for control of the average

wall thickness to reduce wall thickness deviations over the length of the tube and finally for local wall control, which is used to equalise wall thickness deviations – for example, wedges or steps. The measured values can also be used to optimise the processes at the rotary hearth furnace and cross-roll piercing mill. Since the systems are compact, they can be installed directly behind the

From simple to complex MAC has it all.

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• OCTG for oil, gas and water transmission lines • Duplex tube for off shore umbilical applications • Heat exchanger tube for boilers, air conditioners and conduits • ERW and laser welded tubes • Bi metallic tubes for bearings and parts

For ferrous or non-ferrous square, rectangular, round or hex tubular products, MAC provides the best equipment for the only test system that matters — YOURS!

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Nondestructive testing since 1928

Magnetic Analysis Corp. 535 South 4th Avenue, Mount Vernon, NY 10550 (914) 699-9450 Fax: (914) 699-9837 info@mac-ndt.com

See us at Tube 2010 Düsseldorf, Hall 4/Stand 4H19

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