A Novel Method for Detecting the Onset and Location of Mechanical Failure by Correlating Engineering Stress With Changes in Magnetic Properties of UNS S32205 Duplex Stainless Steel Using Quantum Well Hall Effect Sensors

A new method for determining the onset and location of mechanical failure and the associated engineering stress via scanning the magnetic field distribution using a quantum-well Hall effect sensor is presented. From the Villari effect, it should be noted that changes in the magnetic properties of a ferromagnetic material should reflect some characteristics of the mechanical load and engineering stress that the material sustains. In this study, a direct relationship between the measured magnetic field, engineering proof stress (Rp0.2), and plastic deformation is revealed. The experiment was performed on a Grade 2205 duplex stainless steel under tensile loading. Magnetic field studies closely predicted the proof stress of the sample material. Consequently, the DC magnetic field response predicted the location of the plastic failure as early as 2% of the total strain. This new method has significant potential in systems that require condition monitoring and in-situ non-destructive testing to track the onset of plastic deformation in machine components