Characterization of carburization of HP steels by non destructive magnetic testing

In this work, the magnetic measurement technique was explored to classify 13 samples of HP tubes, as their magnetic properties are altered by carburization. The results were validated by comparison of those obtained by optical microscopy and by electronic scanning microscopy for the volumetric fraction of chromium carbides. A probe based on a giant magnetoresistive sensor (GMR) developed to execute this work, confirms the potential of this technique as an effective and simple tool to monitor carburization in serpentines of pyrolysis furnaces since it was possible to establish a correlation between the non destructive magnetic response and the volumetric fraction of chromium carbides.