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- Echo tomogram of phased array probe measurements in V-arrangement (1)
- Gruppenstrahler-Prüfkopf mit 64 Schwingerelementen (1)
- Gruppenstrahlertechnik (1)
- Konventionelle Winkelprüfköpfe (1)
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- Sizing using SAFT (1)
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Zusammenfassung
Aus den Messergebnissen geht hervor, dass der Real-Time-Scanner den Reflektor-nachweis der konventionellen Prüfköpfe hinsichtlich des erreichten S/R-Abstandes erreicht und teilweise übertrifft. Weiterhin geht aus den Ergebnissen hervor, dass die Nachweisempfindlichkeit sehr empfindlich auf Abweichungen der Prüfkopf-positionierung reagiert. Nur wenn die optimale Fahrspur für jede Reflektortiefenlage getroffen wird, kann mit den konventionellen Prüfköpfen ein S/R-Abstand von mehr als 20 dB erreicht werden. Das bedeutet, dass mit den konventionellen Prüfköpfen immer mehrere parallele Fahrspuren mit kleinem Spurversatz gefahren werden müssen, um auch kleine Fehler in der Schweißnaht nachweisen zu können. Mit dem Real-Time-Scanner-Prüfkopf können mit einer einzigen Messfahrt und mit entsprechend vielen angepassten Messfunktionen mehrere parallele Fahrspuren durch elektronisch gesteuerte Bündelverschiebung erfasst werden.
Introduction
Due to the long history of railroad companies around the world, varying means of examination according to the specifications for the different railroad components have been carried out based on the general industrial progress of the country [1-3]. For more than 50 years the application of customized ultrasonic techniques for the examination of railroad components has increased, in comparison to conventional ultrasonic techniques used until to the end of 20th century. In this traditional atmosphere some accidents have disturbed the silent harmony of companies involved in the production of critical parts. More than ever high speed modern trains require modern and advanced examination techniques [4-8]. For practical application new ultrasonic techniques have been developed and optimized in co-operation with the German Railroad Company. In the present contribution the inspection of railroad axles will be described. The ultrasonic technique used for the examination is the phased array technique. The optimization of the phased array probes for the different geometries of the axles given was completed using a computer model for directivity calculations. In relation to the limited accessibility between wheel and brake angles of incidence for shear waves in the range between 28° and 72° are necessary.
During the examination of the axles a a considerable amount of ultrasonic data must be stored (storage of the digitized A-scans). However, due to economic aspects the evaluation of this data should be carried out in a very short time. The whole examination of one axle should not exceed 5 minutes. Therefore we have developed a special evaluation program adapted to the particular problematic of the axle inspection. The build up of the whole inspection system was done with partners from the industry like Krautkramer and a division of the Research Department of the Deutsche Bahn AG. In this consortium the Research Department of the Deutsche Bahn AG was responsible for the specification of the inspection problem, Krautkramer for the organization of the whole technical follow up and BAM for the development and optimization of the ultrasonic inspection technique as well as for the evaluation software. Some examples concerning the optimization process will be described in the present contribution.