Published on 27-Feb-2024

Basic Principles of Magnetic Particle Testing

Basic Principles of Magnetic Particle Testing

Table of Content


Magnetic Particle Testing is a widely used non-destructive testing method as it is extremely simple and faster to apply than other methods.

Part surface preparation is also not that critical when it is compared to other methods.

Magnetic Particle Testing uses small magnetic particles, i.e. iron filings and magnetic fields, to discover defects in the components.

The one criteria that need to be fulfilled is that the component which is being inspected should be made of material that can be magnetized, i.e. ferromagnetic material, for example - cobalt, iron, nickel, etc.

Now, let's move on to the part that describes the principle of magnetic particle testing in detail. 

Magnetic Particle Testing

What is Magnetic Particle Testing?

Magnetic Particle Testing (MPT), also referred to as magnetic particle inspection (MPI) in the field of non-destructive testing (NDT), is a crucial method employed for flaw detection in metallic components. 

This NDT Technique relies on the interaction between magnetic fields and small magnetic particles to identify defects such as cracks and corrosion. Here's a detailed explanation focusing on the specified keywords:

Definition and Purpose of MPT:

Magnetic Particle Testing (MPT), a renowned NDT Method, serves the purpose of identifying flaws in metallic components without causing damage.

It is vital to ensure the reliability and safety of equipment and structures by detecting surface and near-surface defects, including cracks and corrosion.

Use of Magnetic Particles and Fields in Defect Identification:

MPT employs magnetic particles, often iron filings or ferromagnetic powders, in conjunction with magnetic fields to highlight defects.

When a magnetic field is applied, these particles adhere to the surface, forming distinct patterns that reveal the presence of defects.

Defects such as cracks or corrosion disrupt the Magnetic Flux Leakage, causing the particles to cluster around the flaw, and facilitating their detection.