Liquid Penetrant Testing (Visible and Fluorescent )

Liquid Penetrant Testing (LPT), also known as Dye Penetrant Inspection (DPI), is a non-destructive testing method used to detect surface-breaking defects in non-porous materials. The process involves applying a liquid penetrant to the surface of the material, allowing it to seep into any surface defects, removing the excess penetrant, and then applying a developer to draw out the penetrant from the defects, making them visible.

High Sensitivity Penetrant – ability to penetrate fine discontinuities and mark them, excellent wetting ability Cleaner – Chlorine and Sulfur Free , Non corrosive and Non toxic Developer – High sensitivity Developer with fast drying nature. High area coverage when used in aerosols High quality aerosol cans which ensure complete usage of the materials.

  1. Solvent Removable
  2. Water Washable
  3. Solvent Suspendible Developer
  4. Solvent Remover
  5. Available in 420 ml Aerosol Can

There are two main types of Liquid Penetrant Testing: Visible and Fluorescent. Here’s a detailed look at each type:

Visible Liquid Penetrant Testing

Visible LPT uses a penetrant that is visible under normal lighting conditions.

  • Process:
    1. Surface Preparation: The surface of the material is cleaned to remove any dirt, grease, or contaminants.
    2. Application of Penetrant: The visible dye penetrant is applied to the surface and allowed to dwell for a specified period to seep into any surface defects.
    3. Excess Penetrant Removal: The excess penetrant is carefully removed from the surface using a solvent, water wash, or emulsifier, ensuring that the penetrant in the defects remains.
    4. Application of Developer: A developer is applied to draw the penetrant out of the defects and create a visible indication on the surface.
    5. Inspection: The surface is inspected under white light to identify any visible indications of defects.
  • Applications:
    • Suitable for detecting cracks, porosity, and other surface-breaking defects.
    • Commonly used in industries such as aerospace, automotive, and manufacturing.
    • Simple and cost-effective method for a wide range of materials.

Fluorescent Liquid Penetrant Testing

Fluorescent LPT uses a penetrant that fluoresces under ultraviolet (UV) light, providing higher sensitivity.

  • Process:
    1. Surface Preparation: The surface is thoroughly cleaned to remove any contaminants that could interfere with the inspection.
    2. Application of Penetrant: The fluorescent penetrant is applied to the surface and allowed to dwell, seeping into surface defects.
    3. Excess Penetrant Removal: The excess penetrant is removed using an appropriate method, ensuring the penetrant in the defects remains.
    4. Application of Developer: A developer is applied to the surface to draw out the penetrant from the defects.
    5. Inspection: The surface is inspected under UV light in a darkened environment, where the fluorescent indications reveal the presence of defects.
  • Applications:
    • Provides higher sensitivity compared to visible LPT, making it ideal for detecting fine or small defects.
    • Widely used in critical applications where detecting minute defects is crucial, such as in aerospace and nuclear industries.
    • Often used for inspecting components with complex geometries where higher sensitivity is required.