Defect detection in aluminum laser welds using an anisotropic magnetoresistive sensor array

Abstract

For the detection of defects in aluminum laser welds an anisotropic magnetoresistive (AMR) sensor array was implemented in an eddy current testing system. The reliability of weld testing is strongly influenced by the texture of the laser weld whose field response significantly superimposes the defect’s magnetic signature. A finite-element model was used to determine the influence of the weld’s topology on the detection of defects such as porosities and inclusions hosted in the aluminum matrix. When using an AMR sensor array with field sensitivity of better than 1nT∕√Hz defects with a radius smaller than 100μm could be detected and classified.

Hochauflösende Wirbelstromprüfung mittels GMR-Sensorik am Beispiel supraleitender Drähte High Resolution Eddy Current Testing of Superconducting Wires by Means of GMR Sensors

“…B. Anlagenbau, Kraftwerkstechnik, Fertigungstechnik, Verkehrstechnik, Medizintechnik) und können mittels hochauflösender MR-Sensorik noch leistungsfähiger gestaltet werden. Es überrascht demnach nicht, dass in den beiden letzten Jahren eine rasant ansteigende Anzahl von Publikationen beobachtet werden konnte, bei denen GMR-Technologie als Schlüssel-element der elektromagnetischen Materialprüfung zum Tragen kommt [1][2][3][4][5]. Dies verdeutlicht, dass die magnetische Mikrosystemtechnik mit der GMR-Technologie in der zerstörungsfreie Prüfung einen neuen innovativen methodischen Ansatz darstellt und in den kommenden Jahren ein steigender Bedarf an adaptierten GMRSensorsystemen zu decken sein wird.…”

Anisotropy magnetoresistance differential probe for characterization of sub-millimeter surface defects on galvanized steel plate

“…The AMR sensor is advantageous over the coilbased magnetic sensor owing to its sensitivity from DC to a few kHz. To construct the ECT system, many magnetometers have been used, such as inductive coil, 18 hall sensor, 19 Tunnelling Magnetoresistance (TMR) sensor, 13,20 anisotropic magnetoresistance (AMR) sensor, 21,22 fluxgate and superconducting quantum interference device (SQUID). 22 A study shows that SQUID has the lowest noise compare to other sensors.…”

Referencing technique for phase detection in eddy current evaluation

“…In this study, the new differential eddy current testing sensor is suggested which consists of two magnetic sensors with the excitation coil. In the beginning, this research started with an AMR sensor [13,14] which means it only contained a single absolute probe. This sensor module was used in the first attempt of the study to integrate the magnetic field sensor into the ECT probe but when the scanning process was conducted, it is found that the measured signal contained metal and background signals which could be assumed as noises.…”