NDT_ Dye Panetrant Testing

Introduction

This blog demonstrate us the Non Destructive testing which is done in many industries where the test piece is costly or cannot be afforded to be thrown away. NDT test involves use of a dye penetrate over a test material, which by the explained procedure exposes the surface cracks.

Objective

To test the specimen for any surface cracks from a production line using dye penetrate Non Destructive test.

Apparatus

• ·         Cleaning solvent
• ·         Dye penetrant
• ·         Developer
• ·         Material= mild steel

Safety Procedure

·         We have to make sure the ventilation is sufficient, as we are dealing with toxic chemical, ideally we have to wear safety masks but the chemical used in workshop were no damaging so  while performing the experiment in workshop we can only consider the ventilation.

·         The chemicals are reactive; they can also react with the skin and damage it, so we have to wear gloves so that our skin is protected.

·         While mishandling there is a reasonable chance that we can drop or spill some amount of the chemical and they can easily penetrate our normal clothing , so ideally one must be wearing boiler suit in order to avoid the risk, but in the workshop we have very less toxic chemicals so it we were not exposed to the risk and so we neglected it.

Procedure

Clean the specimen; make sure it is nice and clean. Heat the material so that it will expand and prevail the faults and apply the dye penetrant, allow it to soak in to the cracks or faults, allow it suitable time to cool. As soon as the suitable time is elapsed, clean the material using the cleaning solvent, apply it on top of the specimen, the applied dye will make a solution with it, clean it using a rag and make sure there is no contamination left on the surface [make sure that the dye penetrant which is seeped into the cracks are not removed].  Then we apply the developer, and wait to cool down, which will allow the material to contract, and the time for developer to react with the dye. After the suitable time is elapsed the cracks will become visible.

Result

As the suitable time is elapsed for the material to contract and the developer to react the cracks or fault on the surface of the material is visible. We know the exact location of the cracks/faults on our work piece, which were 3 circles.

Conclusion

Dye Pernetrant NDT is a cost effective test, which is used by small industry for quality purposes, this allows us to demonstrate the non visible faults on the surface of material which may result in drop of efficiency in the finished product, so either the specimen is resent to the production line, if it is fix able, or scraped, if not fixable.

engineereverything by Asad Ali is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at www.facebook.com. Permissions beyond the scope of this license may be available at http://engineereverything.blogspot.co.uk/2012/04/copy-right-note.html.