Evaluation of stress concentration of U‐shaped notch based on residual magnetic field measurements

In this research, the correlation between the stress concentration and the residual magnetic field (RMF) of 30Cr steel was investigated. Tensile tests were carried out to measure the RMF signals on the surface of U‐shaped defect specimens. It was found that the tangential RMF signal at the defect area is correlated to the applied load and the stress concentration factor. A new method based on magnetic field to evaluate the stress concentration degree is proposed. This research provides a potential possibility for quantitative inspection of the stress concentration in ferromagnetic steels using the RMF measurements.