Ultrasonic Testing in Industrial Applications

[snowJT]

Has anybody here used ultra sonic testings for internal flaws in metals in the intdustry? If so what purposes did you use it for? Only things I can think of someone using it would be to check inside pipes without turning off the flow...?

 

[FredGarvin]

We sometimes use ultrasonic inspection to inspect turbine and compressor discs for cracks.

 

[snowJT]

is it a fun instrument to use? and does it also tell you how far from the surface it is?

 

[FredGarvin]

I don't personally use the instrument. It is used in our repair and overhaul group. I have seen it used but never been the driver.

 

[PerennialII]

is it a fun instrument to use? and does it also tell you how far from the surface it is?

yeah it does ... other dimensions included if all goes well. There are a number of really advanced ultrasonic testing methods which produce very impressive results regarding the flaw, and in some cases even about its behavior under loading (for example like tofd, toft) ... the "volumetric coverage" is quite different than what you get with 'traditional' ultrasonic testing. Have tested how it goes myself, but quickly came to the conclusion that it's probably better if I stick to modeling the inspection itself rather than try to do it, there is definitely an element of 'skill' involved.

 

[Panda]

I have used simple systems to look for cracks and inclusions in casting especially after welding.
I have seen more complex systems used to look for stress points in plastics by detecting material density changes.

You can tell exactly how deep an inclusion is in a casting and then machine down to it and weld in a fill.

As to fun, it really depends on what your idea of fun is. It doesn't quite come up to a sunny day at Bath RFC with four pints of beer and shouting abuse at the ref, but is probably better than a root canal. Some may think differently though.

 

[Astronuc]

Has anybody here used ultra sonic testings for internal flaws in metals in the industry? If so what purposes did you use it for? Only things I can think of someone using it would be to check inside pipes without turning off the flow...?

UT is a form of non-destructive testing. With the use of UT inspection in manufacturing, the objective is usually to verify that a production piece has a no internal flaw larger than a certain specified size.

UT can be used as part of 'in-service inspection' to monitor the development of flaws during operation or assure that any flaw does not exceed a critical size. Advanced UT can actually image a flaw, and in medical systems, image internal organs.

Here is a reasonably good tutorial on UT - http://www.ndt-ed.org/EducationResources/CommunityCollege/Ultrasonics/cc_ut_index.htm

does it also tell you how far from the surface it is?

'Time of flight' uses time and 'speed of sound' to determine distance. The size of the flaw determines the reflectance of the UT signal. Detailed imaging can be done with sophisticated electronics and signal processing.

 

[snowJT]

very handy site astronuc, thanks!