| ABSTRACT: | WALL THICKNESS MEASUREMENT ON LARGE TUBE DIAMETERS USING PHASED
ARRAYS
C. Delhaes1, S. Nitsche1, O. Dillies2, and H. Lompe3
1Vallourec & Mannesmann Tubes, Düsseldorf, Germany; 2Vallourec & Mannesmann Tubes, Deville les
Rouen, France; 3G. Kauth, GE Inspection Technologies Systems, Huerth, Germany;
The Phased Array Technology brings a new dimension to wall thickness measurement on large tube
diameters ranging from 178 to 339 mm. The rotation of the sound beam is achieved electronically, by
suitable sequential of predefined array probe elements. The Phased Array electronics - in the second
generation now - allows a fast calibration, a flexible adaptation of the sound field geometry, as well as the
realization of most different scanning patterns. The ultrasonic coupling is affected by a rotating water jacket
which is generated in a specially developed test chamber. The wall thickness of tubes can be measured over
a large range of different tube diameters without the need for any mechanical adjustments. Six Phased Array
probes with 128 elements each are arranged symmetrically around the circumference. These arc segments
extend across more than 60¡ of the circumference to ensure a 100 % scanning coverage. A virtual probe is
created by simultaneous activation of up to 32 elements during one cycle. For wall thickness measurement
and lamination testing, these elements are activated in such a way that a perpendicular scanning of the test
object is performed. The results are graphically represented and transferred to a database. Online process
monitoring and a subsequent statistical evaluation guarantee optimum quality assurance.
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