Liquid Penetrant Testing or Dye Penetrant Testing (LPT/DPT) is based on the principle of capillary action and is used to detect surface defects. Penetrant of low surface tension penetrates into cracks that are open to the surface. The liquid penetrant testing method gives the best sensitivity for surface defects and defects up to 0.1 inches can be identified. LPT is a low-cost surface inspection Nondestructive testing method and mostly used in most of the industries where the welding process is required such as Fabrication, Manufacturing, Casting, Forging, and Piping, etc.

Advantages of Liquid Penetrant Testing-

· LPT is used to inspect a wide range of materials.

· Liquid penetrant inspection is easy to perform.

· The visual image of the flaw is generated on the surface of part/product as indications are produced directly on the surface.

· Investment is low as compared to other NDT methods.

· It is a very portable inspection method as it comes in aerosol spray cans also.

· A large part or big area can be inspected with good speed and at a low cost.

Disadvantages of Liquid Penetrant Testing-

· Only surface defects get detected.

· Pre-cleaning is important as contamination may mast the discontinuities or defects.

· It is performed on relatively nonporous smooth material.

· Several operations are required under controlled conditions.

· Chemical handling with precaution is necessary (Toxic, Fire & Waste)

· Metal smearing is from machining, grinding and other operations may inhabit detection. Material may need to be etched prior to inspection.

To remove chemicals, post-cleaning is important.

NDT Level II Liquid Penetrant Testing (LPT) Syllabus

· Introduction

· Principle of Penetrant Testing

· Equipment Involved Review and Exercises

· Liquid Penetrant Testing Procedures Workshop and Group discussion

· Materials

· Evaluation of Indication

· Application of Liquid Penetrant Testing

· HAZARDS Precautions

· Code Requirements Review and Exercises

After successful completion of training, participants will be appearing for the Level II exam.

Participants will be certified as NDT LPT Level II after successfully clearing the exam.