Magnetic particle testing detects surface and near-surface discontinuities in ferromagnetic components. It is one of the fastest ways to inspect a weld for cracking, which is why it is so widely specified on fabrication and structural work.
How it works
The component is magnetised — commonly using a portable yoke placed across the area of interest. Where a discontinuity interrupts the magnetic field at or just beneath the surface, the field leaks out of the material. Fine magnetic particles applied to the surface are drawn to that leakage and gather along the flaw, forming an indication that is visible to the inspector.
Where it is used
Weld inspection on structural steel and fabricated assemblies, and in-service inspection of ferromagnetic components where surface-breaking cracking is the concern. It is often applied to welds after heat treatment to confirm the condition of the finished joint.
What it cannot do
The method only works on ferromagnetic materials. For austenitic stainless steels, aluminium and other non-magnetic materials, liquid penetrant testing is the equivalent surface method. It also will not find deep internal flaws — that requires ultrasonic or radiographic testing. Surfaces must be reasonably clean for indications to form reliably.
Magnetic particle testing with CAST
We perform magnetic particle testing on site and at our Bintulu facility, most often on structural and fabricated steelwork. If you are unsure whether your component is ferromagnetic, send us the material grade and we will tell you whether MT or penetrant testing is the appropriate method.
Call +6086 348 938, email cast@ctne.com.my, or tell us about your inspection.