LAB : 1Dye Penetration test

GROUP MEMBERS : NAME STUDENT IDSHYAM PATEL C0696997KARAN PATEL C0695985J I JO JOSE C0694225MAULIKKUMAR PATEL CO697518

AIMTo detect any defect or discontinuity in the welded joint by using Dye Penetration test.

INTRODUCTIONDye penetrant test is used to detect surface flaws in all non-porous materials such as metals, plastics or ceramics.

The test can be applied to all non-ferrous materials and ferrous materials.

PRINCIPLES Dye penetrant test is based upon capillary action.

The penetrant ( low surface tension fluid ) penetrates into clean and dry surface where there is a defect or discontinuity.

USEDye penetrant test is used to find casting defects.

Dye penetrant test is used to detect forging defects.

Dye penetrant test is used to detect surface defects in welding.

This test is used to find flaws like hairline cracks, leaks, surface porosity in new products.

Also used to find fatigue cracks on working components.

Materials required1. Sample to be inspected for defects

2. Cleaning Cloth

3. Aerosol Solvent for cleaning the surface

4. Dye penetrant

5. Developer

6. Safety gloves

Aerosol, Penetrant and Developer

Samples

Cleaning Cloth

Gloves

THEORYDye Penetrant test or Liquid Penetrant Test(LPT) or Liquid Penetrant Testing (LPT) is widely used all around the world to detect any surface defects in any non porous materials ( metals, plastic or ceramics) due to its low cost and low time for inspection.

For finding very minute defects in non porous materials Fluorescent Penetrant test(FTP) is used.

The Penetrant may be applied to all materials including all ferrous as well as non ferrous materials, but for inspection of ferrous materials magnetic-particle inspection is preferred for its capability to detect sub surface defects.

PROCEDUREStep 1 : Pre-cleaning

First the sample/material for which we have to find the defects has to be cleaned for any dirt, paint, oil, grease or anything that will prevent the penetrant from penetrating into the defects.

Cleaning the

surface

PROCEDUREResult after step 1 :

This part to be inspected should be

thoroughly cleaned

PROCEDUREStep 2 : Application of Penetrant

The penetrant is then applied to the surface of the item to be tested.

The penetrant is the given some dwell time so that the penetrant is soaked into defects by capillary actions.

The dwell time is around 10 minutes to 1 hour depending upon the defect.

Penetrant dye is

applied

PROCEDURE Step 3 : Removal of excess penetrant

The excess penetrant is removed from the surface of the sample .

Do not spray aerosol directly on the sample material as it will remove the dye which has penetrated into the defects, instead clean it by a lint free cloth with aerosol sprayed on the top of the cloth.

PROCEDURE Step 4 : Application of Developer

After the excess penetrant is cleaned, developer is applied.

The developer should be mixed thoroughly before applying on the sample.

Wait for the developer to dry out.

Developer is applied

InspectionWait till the bottling action is completed by the developer( when the developer extracts penetrant from the defects).

Inspection of the sample

Problem due to

insufficient cleaning

Defect/Crack

Advantages of Dye Penetration Inspection

Speed of the test is very fast.

Low cost.

Surface flaws can be detected very speedily.

Disadvantages of Dye Penetration Inspection

Only detects surface flaws.

Conducting on a rough surface such as welding will create difficulty for removing penetrant.

This experiment can only be done on non porous surfaces.

Some experience is needed to perform this inspection.

Precautions and Safety Measures

Always wear safety glasses and shoes while performing this experiment.

Thoroughly clean the surface before applying penetrant.

Allow enough time for the penetrant to penetrate into the defects.

Do not spray aerosol directly on the sample after the penetrant has been applied.

Clean the surface after the penetrant has been applied with a lint free cloth.

Shake well before applying developer and give enough time for the developer to complete the bottling effect.

Result / Conclusion As we can see here that there is a bleed at the end of the welding,

this indicates that there is a surface defect at the end of the welding.

The dye on the other parts of the welding is due to insufficient cleaning and not due to the defects.

Bleed of dye indicates defect