Demagnetization

Definition

Demagnetization is a process of removing a magnetic field from a material or a workpiece. The magnetic field can be generated by various factors, such as the influence of other magnetic fields, electric currents, or magnetizable materials near the workpiece. Demagnetization reduces or eliminates the magnetic force in the workpiece, which can be important to avoid undesired effects such as attracting metallic particles or malfunctioning of electronic devices.

Ferromagnetic steels can become magnetized when exposed to an external magnetic field. This magnetization can be demagnetized through increased temperature (between 100°C and 460°C for ferrites), strong vibrations, or using an alternating field.

Since the TDC® coating is often the final process for many workpieces, high temperatures and vibrations are not desirable. Therefore, we recommend demagnetization using an alternating field.

Process

The residual magnetism can be demagnetized through increased temperature (between 100°C and 460°C for ferrites), strong vibrations, or an alternating field.

Since the TDC® coating is often the final step, high temperatures and vibrations are not desired. Therefore, we recommend demagnetization using an alternating field.

Using a field measuring device, we can measure the residual magnetism. In electroplating, a threshold value for residual magnetism is typically set between 2A/cm and 8A/cm. If an unacceptable level of residual magnetism is present in the component, we demagnetize the parts to the desired limit using an MT test bench.

Specifications

• Material information. 
• Workpiece drawing, if available. 
• Limit for residual magnetism.

Materials

All ferromagnetic materials with a magnetic permeability of µ > 100 can be subject to magnetization. These materials include all types of steel and their alloys, except austenitic steels, cast iron, nickel, and cobalt materials.