How can a part be demagnetized after magnetic particle inspection?

Demagnetizing a part after magnetic particle inspection is effectively achieved by slowly moving the part out of an AC magnetic field of sufficient strength. This process utilizes the concept of alternating current (AC) magnetic fields to gradually reduce the magnetic field strength in the part. As the part is moved out of the magnetic field, the magnetic domains within the material have the opportunity to randomize and lose their alignment, which effectively removes any residual magnetism that might have been induced during the inspection process.

This technique is preferred because it offers a controlled method to eliminate magnetism without risking structural integrity or introducing heat, which could affect the material properties. Additionally, the gradual movement through the AC field allows for a more uniform demagnetization across the entire part, making it an effective technique in ensuring that no magnetism remains that could interfere with subsequent processes or applications.

The other methods may not effectively demagnetize the part. Heating could alter material properties; high-pressure air does not influence the magnetic domains; and submerging in a conductive liquid wouldn’t address the magnetism directly. Thus, the use of an AC magnetic field provides the most effective way to demagnetize parts post-inspection.