Limitations and Errors in Magnetic Particle Testing

Although a “non-glamorous method”, magnetic particle testing or MPT is still one of the most reliable procedures in non-destructive testing (NDT). With proper equipment and qualified personnel, the inspection method is truly straightforward and dependable.

However, it’s still possible to forget about the limitations and incur errors even with the method’s simplicity and reliability. Let’s discuss some of these in this article.

Limitations and errors in magnetic particle testing

First, the inspection method can be quite time consuming depending on the quantity, configuration and other features of the part or component to be inspected. One reason for this is the need for inspecting in two 90° opposing directions. This is to ensure discontinuities are detected regardless of the component’s orientation. Some personnel still forget this and take the shortcut which results in inaccurate detections.

Another limitation of the method is that the material to be inspected should be ferromagnetic. This disqualifies some metals such as magnesium, aluminium and stainless steels. As a result, it’s crucial to know the constituting material of the alloy or part to be inspected. After all, this NDT method heavily relies on magnetism and the flow of current. Errors can be made regarding the detection results if we’re not sure about the constituting material of the object we inspected.

Demagnetisation is another issue because we had to run a magnetic current through the component in the first place. This can be sometimes difficult and time consuming. For example, demagnetising long bars may require changing the direction of the bars with respect to the demagnetiser and the Earth’s magnetic field.

There are several other nuances when it comes to using Magnetic Particle Testing as an NDT method. If you require more information about the method and its necessary equipment, you can contact us here today. We can give you cost-effective solutions according to your specific application.