Penetrant Testing

Penetrant Testing

This is a simple low-cost method of detecting surface-breaking flaws such as cracks, laps, porosity, etc. To be detected, the flaw must reach the surface to be tested.

Penetrant testing is one step up from visual inspection and offers many advantages, such as speed, large-area coverage.

The article addresses a step by step dye Penetrant testing process. There are two techniques for dye Penetrant test as follow:

In this article, we are going to explain the simplest technique and process which is used for portable application in the field. Some of the above-mentioned processes are designed for lab test application and would not be easy to be conducted in the field. Here is the step by step dye Penetrant testing process:

Fluorescent Penetrant are usually used when the maximum flaw sensitivity is required.

The principle of liquid Penetrant testing is that the liquid Penetrant is drawn into the surface-breaking crack by capillary action and excess surface Penetrant is then removed; a developer (typically a dry powder) is then applied to the surface, to draw out the Penetrant in the crack and produce a surface indication. Cracks as narrow as 150 nanometers can be detected. The indications produced are much broader than the actual flaw and are therefore more easily visible.

Liquid Penetrant testing can be applied to any non-porous clean material, metallic or non-metallic, but is unsuitable for dirty or very rough surfaces. Surface cleaning is a vital part of the Penetrant testing technique. The method can be manual, semi-automatic or fully automated. Penetrant inspection, continuous-operation production lines in which the specimens are cleaned, dipped, washed, dried, etc on a time cycle are common.

Recently, equipment to fully automate the visual inspection stage of the process, by robotic handling of the specimen on a programmed procedure with television camera viewing and pattern recognition to identify and recognize flaws, has been introduced. Television image enhancement processes can be included.

A special, very high sensitivity Penetrant process, using radioactive tracers is sometimes used, but requires very stringent safety procedures.

Hardness testing

The application of hardness testing enables you to evaluate a material’s properties, such as strength, materials amenability and wear resistance, and so helps you determine whether a material or material treatment is suitable for the purpose you require.



A hardness test is usually performed by pressing a specifically dimensioned and loaded object (indenter) into the surface of the fabric you’re testing. The hardness is decided by measuring the depth of indenter penetration or by measuring the dimensions of the impression left by an indenter. Hardness tests that measure the depth of indenter penetration include: Rockwell, Instrumented Indentation Testing, and Ball Indentation Hardness Hardness tests that measure the dimensions of the impression left by the indenter include: Vickers, Knoop, and Brinell

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