Magnetic Particle Testing Remanence Field Demagnetization
Magnetic particle testing residual field demagnetization is the process of removing residual magnetism in parts after crack testing to prevent ferromagnetic chips during service.
Physicochemical Mechanism of Action
Remanent field demagnetization uses a decaying alternating field that excites the magnetic dipoles in the metals and then decays slowly. This leads to uniform demagnetization of the component.
Metallurgical Relevance & Welding Risks
An incomplete demagnetization process can lead to adhesion of ferromagnetic chips, which can cause cracks or wear during operation. This increases the risk of safety issues and reduces the component's lifespan.
Workshop Practice & Instructions
After crack testing, the component should be demagnetized in a magnetic particle testing device. The process time is typically 30-60 seconds, depending on the size and material of the component. Make sure the device is correctly calibrated and the prescribed parameters are followed.