On a proposal of the appraisal committee the president of the “Austrian Company for Measurement and Automation Technics” has awarded Dipl.-Ing. Dr. Johannes Atzlesberger with the OGMA-PRIZE 2013 for his Dissertation “Development of a measurement system for detecting subcutaneous inclusions in steel sheet”.
May 22, 2014
In recent years magnetic imaging technologies has become a great concern in non-destructive testing (NDT). Due to the advent of highly sensitive magnetic field sensors based on the GMR-effect (Giant Magneto Resistance) the flux leakage (which depends on magnetic inhomogeneities inside the inspected material) can be measured precisely. During the work on this thesis a testing device was developed (see Figure 1) which is able to detect magnetic flux density variations from mT (millitesla) down to only some nT (nanotesla). Thus defects, corrosion, non-metallic inclusions, surface defects, cracks, specimen thickness variations and even residual stresses can be detected. In Figure 2 the schematic test set-up of the magnetic flux leakage (MFL) method is shown which was already applied - of course in a highly simplified way - in the 19th century for detecting flaws in gun barrels and railway tracks. An electro magnet magnetizes the ferromagnetic specimen and the specimen's surface is scanned with the developed testing device. In Figure 3 an exemplary 2-dimensional magnetic image of a steel sheet containing artificial inhomogeneities is shown. Keywords: Magnetic Flux Leakage (MFL), Giant Magneto Resistance (GMR), Non-Destructive Testing (NDT).
The circulation of the project work is restricted from January 28th, 2013, for a period of 5 years.