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Best Magnetic Particle Testing (MT) Companies

Magnetic particle testing (MT) is a high-sensitivity surface and near-surface inspection method for ferromagnetic materials, using induced magnetic fields and visible or fluorescent magnetic particles to reveal cracks, laps, seams, and other surface discontinuities. MT is extensively used for weld inspection, forging and casting evaluation, in-service inspection of rotating equipment, and structural assessment across oil and gas, aerospace, power generation, and heavy manufacturing. Its low setup cost, fast cycle time, and high sensitivity to tight surface cracks make it the preferred surface inspection method in many fabrication and maintenance environments.

Why these suppliers?

  • ✓MT provides direct visualization of surface and near-surface cracks in ferromagnetic welds, forgings, and castings — higher sensitivity for tight surface cracks than liquid penetrant testing on ferromagnetic materials.
  • ✓Fluorescent MT (wet method, UV-A light) achieves the highest sensitivity for very tight cracks, commonly specified in aerospace and nuclear applications where detection of the smallest flaws is safety-critical.
  • ✓MT technicians certified under ASNT SNT-TC-1A or NAS 410 are qualified to independently evaluate indications and provide reportable inspection results compliant with ASME, AWS, API, and military standards.

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Frequently Asked Questions

What materials can be inspected with magnetic particle testing?
MT can only be applied to ferromagnetic materials — primarily carbon steel, low-alloy steel, cast iron, and some stainless steels. Austenitic stainless steels, aluminum, titanium, copper, and other non-ferromagnetic materials cannot be inspected with MT. For surface inspection of non-ferromagnetic materials, liquid penetrant testing (PT) is the standard alternative.
What is the difference between dry and wet magnetic particle methods?
Dry MT uses dry particle application and is used for rough or elevated-temperature surfaces where wet application is impractical. Wet MT suspends particles (fluorescent or non-fluorescent) in a liquid carrier for more uniform coverage and higher sensitivity, particularly for tight cracks. Wet fluorescent MT (WFMT) is the most sensitive MT method, required for many aerospace and nuclear applications. The applicable procedure specifies the method — do not substitute dry for wet without code and customer approval.
What ASNT certification is required for MT inspection?
ASNT Level II MT is required for independent inspection, interpretation of indications, and report preparation. Level I can assist but cannot independently evaluate indications. For aerospace Nadcap work, NAS 410 Level II is required. Companies performing MT should also be able to demonstrate equipment calibration records, current procedure documentation, and light meter or gauss meter verification records as required by the applicable code.