Interpretation von Ultraschall-Abbildungen

During the evaluation of ultrasonic images, e.g. SAFT-reconstructed B-scan images (SAFT=Synthetic Aperture Focusing Technique) it is often difficult to decide, what is the origin of reconstructed image points: were the caused by defects, specimens geometry of modeconversions. To facilitate this evaluation a tool based on the comparison of data was developed. Different kinds of data comparison are possible: identification of that RF-Signals, which caused the reconstructed image point. This is the comparison of a reconstructed image with the corresponding RF-data. Comparsion of two reconstructed images performing a superposition using logical operators. In this case e.g. the reconstruction of an unknown reflector is compared with that of a known one. Comparison of raw-RF-data by simultanous scanning through two data sets. Here the echoes of an unknown reflector are compared with the echoes of a known one. The necessary datasets of known reflectors may be generated experimentally on refer ence reflectors of modelled. The aim is the identification of the reflector type, e.g. cracklike or not, the determination of position, size and orientation as well as the identification of accompenying satellite echoes. The interpretation of the SAFT-reconstructed B-scan image is carried out by a complete description of the reflector. In addition to the aim of interpretation the tool described is well suited to educate and train ultrasonic testers

Evaluation of ultrasonic volume- and underclad indications at long distances

Analysis techniques are applied in UT examinations if the standard examination provides unacceptable indications and more exact parameters are required for the fracture mechanics evaluation. The necessity for analysis techniques is particularly great where long distances are involved, i.e. when sensitivity is too limited for crack tip detection or when focusing at the reflector location is insufficient, in order to correct the results of the standard, which are often too conservative. There are manual analysis procedures, using focusing transducers or time of flight reconstruction methods, and mechanized, computer-assisted procedures, based on the synthetic aperture principle. ALOK and SAFT measurements were performed by the IzfP (NDE Institute) and KWU on volume flaws and findings near the cladding. The results show that, compared with manual measurements, the computer-assisted methods have the advantage that the complete B-scan representation enables better interpretation of the exam ination interpretation of the examination results, thereby avoiding evaluation errors in individual cases. ALOK reconstruction have the advantage that they can be interpreted in the same way as a manual analysis, thus facilitating for the UT examiner the transition from the manual to the computer-assisted imaging method. Better image reproduction is a feature of the L Saft reconstructions. Virtual independance from examination parameters is also advantageous

Ultraschallprüfsysteme für die Produktionsprüfung von Eisenbahnrädern

In both passenger and freight operation, railway wheels are subject to high dynamic stresses. Highspeed passenger services as well as the transport of cost-intensive and hazardous freight put a premium on high railway wheel quality as a major precondition for safe, fault-free running. Highly-stressed wheels have to meet the requirements of European standard EN 13262. Testing is carried out using ultrasound techniques