Principle Methods Used for NDTs

Non Destructive Test
From this definition alone, one can easily infer that the application of non destructive equipment is geared more in the production of electronic appliances, computers, and other gadgets. The technology is also widely utilized in the construction fields. But the uses of NDT can be wide, and numerous industries are discovering the advantages they can get from such technology.
For a deeper understanding, it is better to start with the introduction of the different non destructive equipment technologies. These can all be broken down into two main classifications: conventional and advanced.

Conventional NDT applications are those that are obviously quaint and can date back to the early 1950s. Then again, a lot of industries still utilized these methods for their daily routine examination. The technologies include:

- Radiography: used in construction sites specifically in welding examinations and detecting corrosion after some of the facilities are placed in service. Radiation-emitting devices including x-rays and industrial films are utilized in this method to produce a latent image.

- Ultrasonic: functions as a reader for the thickness of a material. This is widely utilized for the deeper perusal of inherent flaws in the welding, while performing semi-automatic and automatic modes in mapping out the corrosion of pressure vessels and piping.

- Magnetic particle: used to detect and estimate the size of flaws or defects that are seen on the surface of the materials. This would include crack and delaminating. Subsurface defects like gas holes and inclusions are also located through this method.

- Liquid Penetrant testing – used as oil and powder type of examination years ago to test the soundness of railroad car wheels and their resistance to cracking. At the modern age, though, PT works in the same principle but takes a more sophisticated application. Highly viscous penetrants are sprayed on metals, plastics and concrete. The substance is left to dry, to which professionals would wipe out the excess. Trapped penetrants would reveal the location and size of the defects.

- Visual testing (VT) – probably the simplest yet often overlooked method. The technology involves a remote visual inspection of the product through a bore scope, fiberscope or robotic video devices.
The technology that comes with non destructive testing equipment, however, has changed overtime. Old practices are still carried about, but newer methods are introduced as more innovations and technological advances are introduced.

The following are more modern nonconventional methods of NDT:
- Electromagnetic testing: associated with user-friendly devices. This practice centres on the fundamental theory of electricity and magnetism, and is being utilized in the production testing of non-magnetic tubing and pipe. To explain it simply, magnets are utilized in sorting out materials.

- Acoustic Emission – based on the elasticity of energy that is released when the materials are deformed. This method starts with the detection of the 'tin cry' among examination of tank floor corrosion, pressure vessels and pipeline cracks or corrosion under hydro test.

- Thermal/Infrared
– centres on the detection of energy emitted from any material and temperature differences in the surfaces. This method is applied in testing microprocessor equipment.

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