Nondestructive method of quantitatively evaluating degree of plasticity of steel material

摘要

In a nondestructive method of quantitatively evaluating a degree of plasticity of ferromagnetic materials, a magnetic field of a surface of a ferromagnetic test body is measured using a magnetic sensor, and the surface of the ferromagnetic test body is partitioned into regions corresponding to domains of the ferromagnetic test body. A difference between a maximum value and a minimum value of a magnetic signal corresponding to the magnetic field for each of the domains is calculated as a spatial difference amount. A distribution width of the spatial difference amounts and an amount of residual strain corresponding to an amount of plastic deformation of the ferromagnetic test body is measured. A correlation between the distribution width of the spatial difference amounts and the amount of residual strain is calculated. A degree of plasticity of the ferromagnetic test body in calculated in accordance with the correlation.