Dye Penetrant Inspection (DPI) is widely used to detect surface breaking flaws.

This non-destructive testing technique, also known as liquid penetrant inspection (LPI), is a cost-effective method used to locate surface breaking flaws such as cracks, porosity, laps, seams and other surface discontinuities. Dye penetrant inspection can be applied to both ferrous and non-ferrous materials and all non-porous materials (metals, plastics or ceramics).

The method is also useful for testing on-site as it is portable, and when applying certain techniques such as visible colour contrast there is no need for additional resources such as electricity or water. This makes it a highly convenient for inspecting surface discontinuities.

The tested item is cleaned first before the penetrant is applied by dipping, spraying or brushing. The penetrant is given time to soak into any defects, the penetration time dependent on the chosen penetrant and customer requirement.

Afterwards, the excess penetrant is removed and the component is dried depending on the process used. Then a developer is applied. The developer helps to draw the penetrant out of the flaw and onto the surface to form a visible indication. A visual inspection is then performed by the inspector under ultraviolet or white light, depending on the type of penetrant used (fluorescent or visible colour contrast).

Penetrants are classified by their sensitivity levels and, when selecting a penetrant, factors such as environment under which the test is to be performed, surface finish, size of defects sought and size of test piece are considered.

Our Total Quality Assurance techniques for dye penetrant inspection include:

• Visible solvent removable
• Water washable
• Post emulsifiable

Sreevari's certified team of NDT professional techs offer complete inspection services to an expansive range of industries domestically and globally. Dye Penetrant Testing services are offered in our laboratories, in the field and/or on client premises with customer service as a priority and cost effectiveness as a primary goal.