Tuesday, January 24, 2017

Techshore Inspection Services : Ultrasound Testing Techniques – Contact and Immersion

Comparison between Contact and Immersion 

1.                 To get useful levels of sound energy into a material, the air gap between the transducer or probe and the test material should be removed.  This is done by the help of coupling.
2.                 In case of contact testing method a couplant such as water, gel or oil  is applied between the probe and the surface of the test specimen.  
3.                 In case of immersion testing, the test specimen and the transducer probe are immersed in a water bath.  This arrangement helps to provide a smooth movement of the transducer over the specimen while maintaining consistent coupling.
4.                 With immersion testing, an echo pulse from the front surface of the test material is seen in the signal but otherwise signal interference is the same for both the techniques.

What is Immersion ultrasonic testing and what is its importance in NDT ?

In immersion testing, the transducer is placed in the water, above the test object, and a beam of sound is projected. Water is used to couple the sound from transducer to the test object. Immersion testing is done in two ways 
1.                 Done with squatters where the sound travels through a jet of water 
2.                 By immersing the transducer and test object in a tank of water
The graph of peaks differ slightly using the immersion method. There will be an additional peak called the ‘front wall peak’ between the initial pulse and the back wall peaks caused due to the propagation of sound from one medium to the other (sound wave going from the water to the test material). Initial pulse peak could be ignored by adjusting the ultrasonic tester can be adjusted, so the first peak will reflect the front wall peak. The front wall peak will be  slightly lower than the peak of the initial pulse due to the energy loss encountered when sound wave hit the test material.
Immersion Ultrasonic testing is an important NDT test technique that helps the components and structures to detect internal as well as surface breaking defects, and it helps in measuring wall thickness on hard metallic or ceramic components and structures.






References:
https://en.wikipedia.org/wiki/Ultrasonic_testing

Related blogs :

http://techshoreinspections.blogspot.com/2017/01/Techshore-Inspection-Services-ndt-ultrasonic-testing.html
http://techshoreinspections.blogspot.com/2016/12/Techshore-Inspection-Services-liquid-penetrant-test.html
http://techshoreinspections.blogspot.com/2016/10/ultrasound-testing-techniques-contact.html
http://techshoreinspections.blogspot.com/2016/10/ultrasound-testing-technique-through.html
http://techshoreinspections.blogspot.com/2016/10/ultrasound-testing-techniques-pulse.html
http://techshoreinspections.blogspot.com/2016/10/ultrasonic-testing-techniques.html
http://techshoreinspections.blogspot.com/2016/10/ultrasound-generation-principles-of.html
http://techshoreinspections.blogspot.com/2016/10/ndt-ultrasonic-testing-beam-explained.html
http://techshoreinspections.blogspot.com/2016/10/introduction-to-ndt-non-destructive.html
http://techshoreinspections.blogspot.com/2016/09/techshore-non-destructive-testing-ndt.html
http://techshoreinspections.blogspot.com/2016/09/techshore-inspection-services-explains_6.html

Documents : 

https://www.slideshare.net/techshoreinspectionservices/civil-engineering-process-of-well-treatment-techshore
https://www.slideshare.net/techshoreinspectionservices/ndt-ultrasonic-testing-techshore
https://www.slideshare.net/techshoreinspectionservices/ndt-liquid-penetration-test-techshore

Additional references:
https://www.youtube.com/channel/UCfufdF0-Hs3sLu1IX52ZJYA/videos
http://techshore.in/blog
http://techshore-updates.blogspot.in/
https://techshore-inspection-services.blogspot.in/
https://techshoreinspectionservices.blogspot.in/
https://techshoreinspections.blogspot.in/


You Tube Tutorials :
https://www.youtube.com/watch?v=bfW1eL0aTlU
https://www.youtube.com/watch?v=URlwZ3R94u8
https://www.youtube.com/watch?v=6w9Cl58-p34
https://www.youtube.com/watch?v=ZVnsx5VC77g
https://www.youtube.com/watch?v=3ZD4je9Fbn8
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