Non-Destructive Stress Evaluation of Tool Steel Using Scanning Hall Probe Microscope: Effect of Stress Direction on Three Dimensional Magnetic Fields

摘要

Non-destructive stress measurement methods have been developed. However, there are a few approaches into the effect of stress direction on the nondestructive physical factors. In the present work, a non-destructive and non-contact method using three-dimensional magnet microscopy was applied to stress evaluation of an as-received tool steel (JIS, SKS93). Three-dimensional components of magnetic fields were observed using a scanning Hall probe microscope in order to find the important component which was related to the tensile stress. The observations were carried out under the tensile stress that was less than the yielding stress of the material. It was found that the magnetic field component that was parallel to a tensile loading direction was strongly correlated to stress values.