White contrast paint spray – SALP183

The white contrast paint is a spray used in magnetic particle testing (MT) to create a light, uniform background on the component surface, increasing the visibility of indications revealed by black magnetic spray. It is particularly useful where the part has a dark, oxidised or otherwise unsuitable surface for immediate reading of black indications.

In MT testing, white contrast paint does not directly detect discontinuities; instead, it prepares the surface for visual observation. After the white background has been applied, the component is magnetised using a magnetic detector or magnetic yoke and treated with black magnetic liquid. Where magnetic flux leakage occurs, the particles concentrate and form indications that are more clearly visible against the white background.

The white contrast paint spray for magnetic particle testing therefore improves inspection readability on ferromagnetic materials, particularly during checks on welds, castings, forgings, pipelines, metal structures and mechanical components. It is a consumable complementary to visible magnetic particle testing and is used both for production inspection and for maintenance and quality-control activities.

Its fast-drying formulation allows the area to be inspected to be prepared quickly, while its high covering power produces a uniform background with minimal thickness. This is important because the paint must improve visual contrast without unnecessarily affecting the surface under examination.

In the visible magnetic particle inspection cycle, white contrast paint spray is applied to the area to be checked before using black magnetic liquid. The AC/DC magnetic detector generates the magnetic field in the ferromagnetic component, while black magnetic spray makes visible the indications that may form in the presence of cracks, weld defects or other surface and near-surface discontinuities detectable by the method.

The combination of white contrast paint and black magnetic liquid is useful where the natural contrast of the surface is not sufficient to ensure easy reading. On dark, rough or finished parts that make black particles difficult to see, the white background allows the operator to observe any indications more readily and evaluate them according to the adopted procedure.

At the end of the inspection, the paint can be removed using solvent & cleaner spray, completing the operating cycle and cleaning the inspected surface. The cleaner is therefore the complementary product for removing the white background after magnetic particle examination.

Magnetic particle testing is intended for components made from ferromagnetic materials. For non-ferromagnetic materials, or where the aim is to identify discontinuities open to the surface using a different method, liquid penetrant testing may be considered. SALP183 white contrast paint is specifically intended for use with black magnetic liquid and a magnetic detector in visible MT inspection.

The white contrast paint spray complies with ASME BPVC Section V, Article 7, the technical reference for magnetic particle examination. When used in the correct inspection cycle with a magnetic yoke and black magnetic spray, it improves indication readability and supports more effective observation of the inspected surface.

Applications

• Creation of a white contrast background in MT magnetic particle testing
• Use with black magnetic spray to improve indication readability
• Inspection of components made from ferromagnetic materials
• Verification of welds, castings, forgings and mechanical parts
• Inspection of pipelines, fabricated structures and metal structures
• Checks on dark surfaces or surfaces that do not allow easy reading of black indications
• Use with an AC/DC magnetic detector or portable magnetic yoke
• Quality-control activities in production, maintenance and component acceptance
• MT inspections in accordance with ASME BPVC Section V, Article 7

FAQ – White contrast paint spray

What is white contrast paint used for in magnetic particle testing?
It is used to create a light background on the component surface, increasing the visibility of black indications generated by magnetic spray during MT inspection.

Does white contrast paint directly reveal cracks or discontinuities?
No. White contrast paint does not directly detect discontinuities, but improves visual contrast. The indications are generated by the particles in black magnetic spray during component magnetisation.

Which products are used with SALP183 white contrast paint?
It is used together with black magnetic spray and a magnetic detector or magnetic yoke, which generates the field required to inspect the ferromagnetic component. At the end of the examination, it can be removed with solvent & cleaner spray.

When is white contrast paint useful?
It is useful where the component surface is dark or does not allow black magnetic-liquid indications to be observed easily. The white background makes contrast more visible during visual examination.

Which materials is white contrast paint used on in magnetic particle testing?
It is used in MT inspections on components made from ferromagnetic materials, such as carbon steels and other magnetisable materials compatible with the method.

Which components can be inspected using white contrast paint and black magnetic spray?
The cycle can be used to inspect welds, castings, forgings, pipelines, metal structures and mechanical parts made from ferromagnetic materials.

Why is it important for the paint layer to remain thin?
A thin, uniform background provides the contrast required to read indications while keeping the surface suitable for magnetic particle testing.

How is white contrast paint removed after inspection?
The paint can be removed after examination using solvent & cleaner spray, completing cleaning of the inspected surface.

What is the difference between white contrast paint for magnetic particle testing and white developer for liquid penetrant testing?
White contrast paint is used in MT inspection as a contrast background for indications from black magnetic spray. White developer is used in PT inspection to draw out and make visible indications generated by red penetrant.

Which standard applies to white contrast paint?
White contrast paint spray complies with ASME BPVC Section V, Article 7 for magnetic particle testing.

Is a batch certificate supplied?
Yes. Each supply is accompanied by its batch certificate, useful for documenting the batch of consumable used during inspection activities.