Magnetic particle examination is a cost effective and efficient method of testing ferromagnetic components for discontinuities that are near or open to the surface. Magnetic particle testing is widely used throughout various industries to locate surface and near surface defects such as cracks, laps, seams, inclusions, voids and pits. This techniques can be performed in-house or in the field on a wide variety of manufactured materials and components. At LBNiW we utilize magnetic particle testing to inspect:

• New fabrication welds for code compliance
• Castings, forgings, valves and their components, machined parts, pressure vessels, storage tanks, cranes and structural steel welds
• In-service welds and components

Magnetic particle testing works by magnetizing a ferromagnetic specimen using a magnet or special magnetizing equipment. If the test object has a discontinuity, the magnetic field flowing through it is interrupted and leakage field occurs. Magnetic particles applied to the surface of a specimen are attracted to leakage fields and cluster to form an indication directly over the discontinuity. The indications are visually detected under proper lighting conditions which allow a qualified inspector to assess location, size, shape and extent of these imperfections.

Magnetic particle inspection comprises the following basic steps:

1. Pre-cleaning of component
2. Magnetization of test object
3. Application of magnetic media
4. Interpretation of magnetic particle indications

It is crucial that particles have an unconstrained path for migration to both strong and weak leakage fields. Therefore, the test object should be clean and dry before beginning the inspection process. The presence of oil, grease or scale may compromise the inspection.

LBNiW offers in-house and on-site magnetic particle inspection services using yoke type magnetizing equipment. All our MT specialists are certified to level 2 according to ISO 9712 (EN473). They are well-trained inspectors that have good understanding and experience in both the method of inspection and the nature of the industries they are working. They follow strict testing procedures and industry standards that prescribe how inspections should be performed and/or special considerations to be employed. Our experts utilize up-to-date, properly calibrated equipment which guarantees accurate and consistent results.

• Fast method of inspection. Immediate indications are visible directly on the specimen surface
• Very good sensitivity to fatigue cracking, hydrogen induced cracking, and stress corrosion cracking
• Very portable inspection especially when used with battery powered equipment
• Can detect both surface and near subsurface indications, and these are the most serious ones as they concentrate stresses
• The method can be adapted for site or workshop use
• Considered low cost compared to many other NDT techniques
• Large or small objects with irregular shapes can be examined easily

• It is limited to ferromagnetic materials and cannot be used on austenitic stainless steel
• Most methods need a supply of electricity
• The method cannot be used if a thick paint coating is present
• Spurious, or non-relevant indications, are probable, and thus interpretation is a skilled task
• Cannot detect deep subsurface flaws
• Some applications require parts to be demagnetized after inspection