Non-ferrous metal components have been widely used

but present magnetic detection methods are not effective for their detection. A method for non-ferrous metal electromagnetic defect inspection based on magneticfield measurement is put forward. By introducing direct current to non-ferrous metal

a constant magnetic field will be excited on surface of non-ferrous metal. As cracks exist on surface or inside of non-ferrous metal

current distribution inside non-ferrous metal changes

which causes heteromorphosis of external magnetic field

so that tiny cracks on surface and inside defects can be detected by using gradient magnetic field sensor with high sensitivity. Taking copperplate as an example

simulation models are set up to analyze characteristics of magnetic field on surface in all directions. Results of experiment indicate that the maximum variation of measured magnetic field is linear relation to characteristic parameters of crack

which provides a new method for non-ferrous metal detection.