Detection of plastic deformation of 304 austenitic stainless steel based on DC magnetization

The quantitative evaluation of plastic deformation in 304 stainless steel based on DC magnetization means is experimentally studied in this paper. First, specimens of two different shapes are designed and fabricated with 304 stainless steel. Various tensile plastic deformations are introduced into the specimens, and the surface residual plastic strains of specimens are measured by using an optical strain measurement system. Second, the specimens with different residual strains are magnetized by using an electromagnetic magnet, and the residual magnetic fields of the damaged specimens are measured by using a fluxgate magnetometer. Finally, the amplitudes and their relation of the residual strain and the residual magnetic field of different specimens are extracted and investigated. It is found that the distribution of residual magnetic field can be use to distinguish the damage state in material of 304 stainless steel, and the amplitude of residual magnetic field increases with the amplitude of residual strain, which indicates a possibility to quantitatively evaluate the plastic deformation of 304 stainless steel through DC magnetization means.