NDT TRAINING METHODS IN CHENNAI

LIQUID PENETRANT TESTING (LPT)

INDRODUCTION

PT can apply to detect surface discontinuities which are open to surface and also not extremely rough or porous. This method applied to Metals, Glass, Ceramic, Rubber, and Plastic. PT can detect only surface discontinuities i.e. Cracks, Porosity, Laps, and Pin holes in weld.

PROCEDURE

ASME Sec V Article 6

STANDARDS

ASME Sec V Article 24 - SE165

REFERENCE STANDARDS:

ASME Code Section V / Article 24

ASTM-E165-Standard Test Method for Liquid Penetrant Examination.

ASME Code Section I

ASME Code Section VIII

ANSI/ASME B31.1, B31.3

AWS D1.1

Clients specification requirements for acceptance criteria.

PRINCIPLE

Capillary action

TYPES OF ACTION

After applying the Penetrant, it will enter into the opening or discontinuity of the job. This is called as capillary action. The developer is having the blotting effect. So it brings out the Penetrant from the discontinuities. It is called as Blotting effect.

PT EQUIPMENTS

PENETRANT (Green, Red, Pink)

DEVELOPER (White)

PENETRANT REMOVER / CLEANER (Colour less)

LINT FREE CLOTH

LUX METER.

UV METER

ADVANDAGES

Even small fatigue discontinuities on the surface not usually detected by other NDE method can be detected by PT.

Parts with complex geometric are routinely inspected.

Any non-porous material can be tested.

Large areas and large volumes of parts/materials can be inspected rapidly and at low cost.

DISADVANDAGES

Only surface discontinuities can be finding through this method.

Temperature should be maintained at 5 to 52 C on the test job.

PT can't be conducted for porous material. (E.g. Grade 14 cast iron)