Evaluation of the Magnetic Permeability for the Microstructural Characterization of a Duplex Stainless Steel

Abstract

Non-destructive testing has been commonly used to assess the presence of discontinuities that may affect the integrity of materials in service. In this study, a Hall-effect sensor is used in a methodology developed to study, in a non-destructive manner, the microstructural variations of a material that occur because of the single-phase decomposition. The material selected was the UNS S31803 duplex stainless steel, particularly because of its behavior at temperatures below 525 degrees C. Measurements of magnetic permeability based on Hall voltage values were performed, as well as hardness measurements and x-ray diffraction studies. The results confirm that the magnetic permeability can be used to successfully track the formation of alpha' phase from alpha phase in a duplex stainless steel.