Magnetic Particle Testing
Definition - What does Magnetic Particle Testing mean?
Magnetic particle testing is a non-destructive process used to detect surface and subsurface discontinuities in ferromagnetic materials like nickel, cobalt, iron and their alloys. Magnetic particle testing uses small magnetic particles and magnetic fields to find flaws in various products such as forgings, castings and weldments. Many industries use the process to determine the component's fitness for use.
Magnetic particle testing is also known as magnetic particle inspection. Magna fluxing is the popular name used for magnetic particle inspection.
Corrosionpedia explains Magnetic Particle Testing
A magnetic field is used in the process of magnetic particle testing. The material to be tested is magnetized by indirect or direct magnetization. A magnetic field is formed when an electric current passes through the test material; direct magnetization occurs during this phase. Indirect magnetization occurs when the electric current is not passed through the test material and the magnetic field is applied with outside help.
The magnetic flux leaks from a subsurface or surface discontinuity in the material, because air is not as capable of supporting as strong of a magnetic field per unit volume as metals are. After this step ferrous iron particles are applied to the material.