Liquid penetrant testing is a non-destructive (NDT) service that detects surface-breaking faults, such as fractures, laps, cracks, and porosity. Here, we’ll explore the 6 steps of the liquid penetrating testing process.
What is Liquid Penetrant Testing
Liquid or dye penetrant testing is one of the most commonly used NDT services. Through capillary action, this testing process uses coloured penetration liquid to discover and detect any surface imperfections. Metals, glass, rubber, ceramics, and plastics are among the materials that are evaluated with this technique.
The 6 Steps of the Liquid Penetrating Testing Process
Below are the 6 essential steps of the liquid penetrating testing process:
Step 1: Pre-clean part
This can include everything from grinding and wire brushing to simply washing the part off with a rag dampened with the cleaner/remover. Dirt, rust, scale, paint, oil, and grease must be removed from the surface, and it must be smooth enough to wipe away the penetrant without leaving any trace behind.
Step 2: Apply penetrant
In this step, the penetrant will be sprayed or applied using a brush. To enable the penetrant to effectively permeate into cracks and cavities, a dwell (soak) duration is critical. This can take anywhere from 5 to 30 minutes, but never too long to the extent that the penetrant has dried. During the penetrant application, all manufacturer’s guidelines and recommendations must be adhered to.
Step 3: Remove penetrant
Excess penetrant must be removed with clean, dry, lint-free cloths until completely clean. The cleaner or remover should then be sprayed on a clean, dry, lint-free rag and vigorously rubbed over the component until no more penetrant is evident on the rag.
Step 4: Apply developer
On the test area, apply a thin, light coating of the developer. To allow the dye to exit the cracks and form an indication (flaw) in the developer, a dwell time must be observed. A developer normally has a dwell duration of 10 to 60 minutes. Similar to the second step, the guidelines and recommendations provided by the developer manufacturer should be strictly followed.
Step 5: Inspection of the test surface
It is essential to evaluate the test area within the time range specified in the prescribed. As the penetrant bleeds out, the length of an indication can extend, turning an acceptable indication into a rejectable flaw.
Step 6: Post-inspection cleaning
The last step in the liquid penetrating testing process is to clean the test area. This is to ensure all remnants of the developer are completely removed after the evaluation.
Providing Responsible Liquid Penetrating Testing Process
Xpert Engineering Solution specialises in a myriad of NDT methods and is proud to be Malaysia’s leading NDT company. We offer a comprehensive suite of NDT services, including liquid or dye penetrant testing services, to assure the quality of your components or materials. For more information about our solutions, feel free to contact our responsive team.