The German version of this paper was presented at the DGZfP Symposium Wissenschaftliches Kolloquium Grundlagen der Zerstörungsfreien Prüfung(Research in NDT) during the MTQ Exhibition Report 12.-15.11.1996 in Dortmund D.

Table of contents |Full Text|

1 Introduction
2 Phased Array Principle
3 Broad-band Probes with Composite Crystal Technology
4 Universal Phased Array Probe
5 Potential NDE Applications for the Phased Array Ultrasonic Probe
6 Summary and Outlook
7 References

1. Introduction

The codes and standards stipulate performance of ultrasonic examination within the scope of mechanized inservice inspections (ISI) of welds in nuclear power plants. Inspection systems with various scanning directions and angles of incidence including tandem functions are used for this purpose. Because space is limited, it is frequently impossible to mount all of the essential conventional probes on a single inspection system at any time. Time-consuming conversion work involving a high dose rate exposure and multiple scanning passes are the inevitable consequences of this. Development activities have therefore been concentrated on replacing conventional UT probes with phased array probes. One UT phased array probe replaces several conventional probes.

The phased array probe is a UT probe in which the angle of incidence is controlled electronically by means of a suitable ultrasonic instrument. Digital beam angle adjustments are made in the horizontal and vertical directions as appropriate to the geometry of the item to be inspected (orientation of welds to be examined relative to probe). The phased array probes used up to now are large with a partially restricted useful angle of incidence range - in effect, they were all special-purpose probes.

The aim of development work was to design a probe which would meet the following requirements:

1. Compact design
2. Angle of incidence from 0° to more than 70° in steel (Fig. 1).
3. Broad band
4. UT examination with wave mode conversion and tandem functions
5. Good sensitivity
6. Good signal-to-noise ratio
7. Rugged design

Author:

J. Ritter,
works many years in the development department
for Siemens KWU, Erlangen
E-Mail: RITTE00J@erls16.kwu.siemens.de
Siemens in NDT online exhibition