MAGWERKS

Magnetic particle inspection is ideal for detecting surface and near-surface discontinuities in ferromagnetic materials. It is fast, relatively simple to apply, and highly effective for finding cracks, seams, laps, and other defects in parts such as shafts, forgings, castings, and welds.

The component must be made from a ferromagnetic material, such as many steels, iron, nickel, or cobalt alloys. The part must be capable of being magnetized and demagnetized. If you are unsure about your alloy, our team can help you determine suitability for MPI.

Dry powder is typically used on rough surfaces, parts at elevated temperatures, or in field applications where wet systems are not practical. Dry particles are often preferred for detecting subsurface indications on heavy sections and in situations where portability is critical.

Wet method MPI is used for smooth surfaces and where higher sensitivity and better particle mobility are required. It is the most common choice for production wet benches and automated systems, especially when fluorescent indications will be evaluated under UV light.

Surfaces should be free of heavy rust, scale, oil, grease, and loose paint that could block the magnetic field or prevent particles from gathering at a discontinuity. Light coatings are sometimes acceptable, but proper cleaning and pre-inspection preparation are essential for reliable results.

Many water-based concentrates include rust inhibitors, but protection depends on bath makeup, material type, and exposure time. In many cases, parts still require post-rinse drying and a suitable corrosion protection step, especially for carbon and low-alloy steels.

Yes. Water-based baths can be more prone to microbial growth and contamination, so they require regular monitoring, filtration, and concentration checks. Following the product data sheet and implementing a documented bath maintenance program is strongly recommended.

Particle depletion is usually related to inadequate agitation, poor filtration, drag-out on large or heavily wetted parts, or lack of regular bath maintenance. Verifying concentration with a settling test and following manufacturer guidance will help maintain sensitivity.

Yes. Both oil-based and water-based carriers can lose volume over time due to evaporation or drag-out. This changes particle concentration and can affect indication brightness. Routine checks and adjustments are required to keep the bath within specification.

Alternatives include bulk suspensions applied with pump sprayers, recirculating systems, or manual flow-on methods designed for field or bench applications. These options often provide better control over coverage, cost, and waste than single-use aerosols.

White contrast paint improves visibility of non-fluorescent indications, but it must be applied in a thin, even coat and allowed to dry completely before applying particles. Excessive buildup can mask fine indications and should be avoided.

Use compatible solvents or mechanical cleaning methods that do not damage the base material or part geometry. Always follow the coating and solvent manufacturer recommendations, and consider any downstream finishing or coating operations when choosing a removal method.

Many MPI materials are rated up to approximately 120 °C (248 °F), but limits vary by product. Always confirm the allowable temperature range in the technical data sheet before inspecting hot parts, and use high-temperature products when required.