The Magnetic Particle Examination (MT)
The magnetic particle examination is able to reveal finest cracks and fissures on, and slightly under the surface of ferromagnetic materials like cast iron or steel. In addition, the magnetic particle examination is based on the creation of high contrast indications of - otherwise hardly detectable - fissures.
For magnetic particle examination, the sample is flooded by a magnetic flux either entirely or in several sections by use of different magnetization techniques. Fissures interrupt this flux and create a leakage flux, which can be visualised by ferritic particles. These particles settle down at the surface defect and produce well detectable indications.
Similar to the liquid penetrant examination the evaluation of the magnetic particle indications occurs in daylight with color-contrast-test-agents and under UV-light with fluorescent-test-agents.
Compared to the liquid penetrant examination the examination time per part is remarkably shorter and the process-related reliability is much higher, especially at recurring inspections.