Reviewing Crack Detection via Dry Penetrants Inspection

by Aaron Brown reconditioning engines

Science and technology have advanced a lot and this is why companies are never short of ideas when it comes to methods of crack detection. In most cases, you’ll find them using some very popular processes out of which some are being discussed in this post.

CD via Dry Penetrants Inspection

This method is mostly used for materials like carbon steel and is also given the name of DPI, Liquid Penetrants Inspection (LPI) or Penetrants Testing (PT).
This happens to be a low cost method exercised for locating cracks and other microscopic flaws in different non-porous materials.
This can include anything like plastic, metals, ceramic and others.
Experts say that this method can be used for locating different surface breaking defects and casting, forging and welding surface defects.
This would include hairline cracks, surface porosity, leaks in new products, and fatigue cracks on in-service components.

What This Process is all About?

In DPI, experts use capillary actions where a low-surface-tension fluid is released to penetrate into clean and dry surface.
With its help, several flaws mentioned above can be detected in no time.
Experts say that these penetrants can be applied on the surface of the component through dipping, spraying, or brushing.
Once the penetrants are given sufficient time to settle in the surface, they are removed and a developer is applied to fetch them out from the defects present in the surface.

Listed Below are Some Common Pros and Cons of This Method.

Pros:

It is a relatively uncomplicated process
With this process, even small surface-breaking defects can also be detected
It is known as an inexpensive process of them all
There are very few material limitations
It allows the inspection of large, small and even the objects that are geometrically complicated
The process uses very portable components like portable (aerosol spray cans)

Some Notable Disadvantages or Cons are –

Pre-cleaning always stays a very critical point
There is nothing like depth sizing involved in this process
With its help, only relatively non-porous surfaces can be inspected
It’s necessary to have a direct access to the surface under test
Experts say that surface finish and roughness can affect inspection sensitivity
There are no provisions of computerized record keeping
Post-cleaning is required in this process
Care has to be shown during chemical handling and proper disposal is also necessary

NDT or Non-Destructive Testing

Some of the Top Pros or Advantages of NDT are:

Its highly sensitive to surface and subsurface defects
It is capable of performing crack detection even through multi-layered structures and components
With its help, engineers can even detect the flaws through a thin non-conductive surface coating
Only very little pre-cleaning is necessary for this process
The testing equipment’s are very portable, light and easy to use

Some Notable Pros of NDT Technique of Crack Detection are –