Micromagnetic Quantitative Prediction of Stress in DH Steel

Ferromagnetic materials underwent plastic deformation under stress, which in turn caused damage to the components. Nondestructive testing could protect the components from hazards. In this paper, the micromagnetic detection technology was proposed to quantitatively evaluate the stress and plastic deformation of DH steel. According to the stress-strain curve of DH steel, tensile specimens with different amounts of deformation were obtained. The tangential magnetic field, Barkhausen noise, incremental permeability and eddy current signals were synchronously acquired by the micromagnetic detector on DH steel. The feature parameters of the four types of signals were extracted. The coefficient of variation was used as an index to evaluate the repeated detection performance of the micromagnetic detector. The related feature parameters were selected as the input of the multiple linear regression model. The results showed that the incremental permeability signal was the most sensitive to stress. The absolute errors of the multiple linear regression model for stress and plastic deformation were ±1.5% and ±40 MPa, respectively.