At present, the standard inspection methods for commonly used forgings include: magnetic particle inspection, penetration test, eddy current test, ultrasonic testing, etc.
1. The magnetic powder test method is widely used to inspect the surface or near surface defects of ferromagnetic metal or alloy forgings, such as cracks, white spots, hair lines, layers, non-metallic inclusions, etc. This method is only applicable to the inspection of ferromagnetic material forgings.
2. In addition to inspection of magnetic material forgings, osmotic inspection can also check the surface defects of non ferromagnetic forgings, such as cracks, looseness, folding and so on. It is generally used only to check the surface defects of non ferromagnetic forgings, and the defects of the internal structure can not be found.
3. Eddy current testing is used to check the surface or near surface defects of conductive materials.
4. The ultrasonic inspection method is used to check the internal defects of the forgings, such as shrinkage hole, white spot, heart crack and slag. This method is easy to operate, fast and economical, but it is difficult to determine the quality of the defect accurately.