measuring systems for tubes the existing ultrasound wall thickness measurement system and create a...
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APPLICATION REPORTEN
MEASURING SYSTEMSFOR TUBES
ONLINE MEASUREMENT OF „HIGH COLLAPSE“ PIPES
VALLOUREC & MANNESMANN TUBES, RATH PLANT
THE CUSTOMER
The V & M Deutschland GmbH, a subsidiary of Vallourec & Mannesmann Tubes, operates two hot-rolling mills in Düsseldorf, Germany: a plug mill and a pilger mill, with a total annual output of around 370,000 metric tons. The plug mill rolls pipes of up to 16“ OD. The program also includes square and rectangular hollow sections (MSH). The wide range of products includes casing and line pipes for the oil and gas industry, boiler tubes and mechanical and structural tubes.
THE REQUIREMENTS
“High Collapse” tubes are subject to the highest quality standards. Each tube must be checked individually and its collapse load must be computed, based on parameters like minimum, average and maximum outer diameter, wall thickness, out-of-round and eccentricity. As part of a continuous improvement strategy, the manual data acquisition and the accuracy of the manual sample measurements used for this computation should be improved.
Extending the scope of these measurements, yet reducing the efforts, V & M decided to establish an online control of the “high collapse” tubes. A new measurement system for diameter, out-of-round and length of the tubes would complement the existing ultrasound wall thickness measurement system and create a “digital finger print” of every single tube for computation of its collapse threshold. Furthermore, V & M customers require especially tight tolerances for the tube ends to optimally match other tubes. This will avoid flow turbulences in the pipes and thus increase the capacity. All measure-ments should be carried out fully automatic within the cycle time of the plant. Last not least, the new system should fit in the existing plant equipment without major modifications.
THE SOLUTION
An encapsulated measurement frame incorporating two LAP Laser Scan Micrometers arranged under 90° angle to measure diameter and out-of-round was integrated into the existing feeding conveyor of the US measure-ment system. The tube length is measured via two laser photocells along a reference distance. Conveyor rolls arranged under an angle of 45° let the tubes spiral through the measurement system, ensuring continuous measu-rement of the tubes in two axes over the entire length. Due to the compact measurement frame, the high measurement accuracy and the simple opera-tion, the LAP solution prevailed over competing solutions using CCD cameras or Structured Light Imaging systems.
VALLOUREC & MANNESMANN TUBES, RATH PLANT
“Each single tube now carries its own finger print. LAP responded extremely well to our requirements during the develop-ment stages, and the joint development of the complex algorithms quickly lead to convincing results”.
DR.-ING. CHRISTOF DELHAES MANAGER NON-DESTRUCTIVE TESTING V & M DEUTSCHLAND GMBH
THE FINGER PRINT OF EVERY TUBE
THE MEASURING PRINCIPLE:LASER SCAN MICROMETER
LAP Laser Scan Micrometers consist of a transmitter and a receiver unit. A rotating polygon mirror in the transmitter scans the beam of a semiconductor laser in a parallel movement through the measurement fi eld. In the receiver unit, the scanned laser beam is focused back on a photodiode. With a tube in the measurement fi eld, the laser beam gets temporarily interrupted during the scan cycle. The duration of the interruption is measured and the diameter is computed precisely. Neither material chemistry nor surface temperature aff ect the measurement accuracy. The high scanning speed of the LAP Laser Micrometers provides for precise measurements even when the measured tube moves laterally in the measurement fi eld.
OPTIMUM SAFETY
The LAP measurement system automates and accelerates the computation of the collapse resistance of every tube with the required precision. The measu-rement results for wall thickness, outer diameter and out-of-round are classi-fi ed in length segments according to their true position as required by the technical rules, ensuring their general acceptance. The results of the diameter measurement complement those of the US measurement system. Plausibility checks and the correlation of wall thickness and outer diameter allow easy interpretation of the data.
IMMEDIATE INFORMATION
The results of the diameter and the out-of-round measure-ments get combined with the results of the US inspection and are displayed in the control pulpit as numerals and line charts. The system permanently compares the results with the aim sizes, thus allowing the operators to immediately react in case warning or tolerance limits are exceeded. If only an end of a tube is out-of-tolerance, it gets trimmed by the off -size length determined by the measurement system so that the remaining length of the tube meets the tolerances, thus further increasing the yield of the rolling mill.OPTIMAL PRODUCTION CONTROL
The measurement data, along with other order and production relevant data, are stored in a central database. Employees in both production and quality control can access these data, allowing each department to determine specifi c reactions on particular circumstances. Evaluation of these data also allows optimization of the rolling as well as of the hot straightening after the heat treatment, e.g. to eff ectively use the existing tolerance bands. The measurements are carried out fully automatic, drastically reducing the time compared to the previous manual measurements and reducing the workload of the operators. GAP-FREE DOCUMENTATION
With all tube dimensions and associated order and produc-tion relevant data archived in the central database, conti-nuous production documentation is warranted.
Emitter
Laser
Rotating Mirror
PhotocellOptics Optics
Receiver
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EQUIPMENT DETAILS
GENERAL DATA Measured Material: Seamless hot-rolled pipe Measurement tasks:
Pipe OD: Min., Max., Average Out-of-round: Max. value (6 test criteria) Precise longitudinal allocation of measurement data within each segment
Diameter range: 177.8 to 406.4 mm (7 to 16“) Length range: 6 to 15 m (20 to 49’) Material temperature: 0 to 40 °C (32 to 104 °F) Feed speed: 1 m/s (200 fpm)
GAUGING SYSTEM Dual-axes measuring frame with two pairs of LDM 304/305 DSP in large diameter arrangement. Measuring range 1 to 425 mm (0.04 to 16.73“) Resolution 0.005 mm (0.0002“) Accuracy < ±0.05 mm (±0.002“) Measuring rate 400 Hz
MECHANICAL ARRANGEMENT Installed at feeder conveyor for Ultra sound test system #12 Pipes are spiraling through the measurement system
ROLLING MILL DUTY DESIGN Virtually maintenance-free through self-monitoring laser sensors Rugged mill-duty steel measuring frame, annealed for stress relief Autonomous air supply unit with air conditioning and high efficiency filters for cooling and air purging of the measuring frame
TEST SEQUENCE Fully automatic measurement sequence without any operator input, start/stop trigger through laser sensors Length measurement with laser photocells along reference distance Continuous monitoring of actual vs. nominal size, with output signals for tolerance limit violations Quick and easy on-site calibration using certified master pieces
INTEGRATION IN PRODUCTION LINE Real-time display of measurement data with signaling of tolerance violat-ions on monitors in the control pulpit of the US test system Ethernet data link to central V & M data base for archiving of individual pipe data System status monitoring with event and alarm logging
SERVICE AND MAINTENANCE Availability: close to 100 % Maintenance: virtually maintenance free; replacement of air filters as nee-ded, estimated after 6–9 months Stability: The gauge proves excellent long-term stability, hence very low effort is required for system calibration. Even months after system commissi-oning, no deviations had occurred.
LAP GmbH Laser ApplikationenZeppelinstrasse 2321337 LueneburgGermanyPhone +49 4131 9511-95Fax +49 4131 9511-96Email [email protected]
LAP Laser, LLC1830 Airport Exchange Blvd.Suite 110Erlanger, KY 41018USAPhone +1 513 271-4529Fax +1 513 271-3821Email [email protected]
LAP GmbH Laser ApplikationenПредставительство в Москве1, Казачий переулок 7119017 МоскваРоссийская ФедерацияТел. +7 495 7304043Факс +7 495 7304044Email [email protected]
LAP Laser ApplicationsAsia Pacific Pte LtdBlk 750A #07- 08Chai Chee Road Technopark@Chai CheeSingapore 469001Phone +65 6536 9990Fax +65 6533 6697Email [email protected]
LAP Laser Applications Asia Pacific Pte Ltd Shanghai Representative Office #1903 World Trade Tower 500 Guang Dong Road, Huangpu District Shanghai 200001 ChinaPhone +86 (21)5047-8881Fax +86 (21)5047-8887Email [email protected]