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916 views
01:20 Jun-02-2008
Paulo
Porosity on TOFD inspection

Hello everybody,
Please I need a help concerning the Porosity on TOFD inspection. I couldn't find a specific criteria for porosity cluster. Can anybody help me?
Thanx!
Paulo


 
03:38 Jun-02-2008

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1208
Re: Porosity on TOFD inspection Paulo:
Acceptance criteria will depend on the Code you work to. Unfortunately too many codes are still trying to make ultrasonic results look like radiography. If you can, with great certainty, declare that a TOFD indication obtained from a single line scan (D-scan) is a cluster of porosity, then your assessment skills and confidence is greater than mine.
An upper "tip" signal will be possible with a cluster of pores (it is likely to look like an irregular set of arrival times). The lower boundary of the indication from such a flaw will be VERY difficult to determine. Inter-pore scatter will generate several paths that will be unresolvable from the diffraction off the lowest portion of the flaw.

It is permissable in some Codes to assess pores as if they were planar flaws then a length needs to be determined.

Ed

----------- Start Original Message -----------
: Hello everybody,
: Please I need a help concerning the Porosity on TOFD inspection. I couldn't find a specific criteria for porosity cluster. Can anybody help me?
: Thanx!
: Paulo
------------ End Original Message ------------




 
07:44 Jun-03-2008
Paulo
Re: Porosity on TOFD inspection Ed,
First of all, thanks for your help.
So, what you are saying is that is quite impossible to assess porosity using only TOFD method? Cause it's impossible to know the correct position of the flaw on the scan axis, we just know the depth!
Thanks

Paulo

----------- Start Original Message -----------
: Paulo:
: Acceptance criteria will depend on the Code you work to. Unfortunately too many codes are still trying to make ultrasonic results look like radiography. If you can, with great certainty, declare that a TOFD indication obtained from a single line scan (D-scan) is a cluster of porosity, then your assessment skills and confidence is greater than mine.
: An upper "tip" signal will be possible with a cluster of pores (it is likely to look like an irregular set of arrival times). The lower boundary of the indication from such a flaw will be VERY difficult to determine. Inter-pore scatter will generate several paths that will be unresolvable from the diffraction off the lowest portion of the flaw.
: It is permissable in some Codes to assess pores as if they were planar flaws then a length needs to be determined.
: Ed
: : Hello everybody,
: : Please I need a help concerning the Porosity on TOFD inspection. I couldn't find a specific criteria for porosity cluster. Can anybody help me?
: : Thanx!
: : Paulo
------------ End Original Message ------------




 
05:30 Jun-04-2008

mustafa GONULAL

Engineering,
CIMTAS / ENKA,
Turkey,
Joined Jun 2008
8
Re: Porosity on TOFD inspection Hi, I am a TOFD expert, I have inspected 20km weld with TOFD method. I have seen many clusters of porosity in a weld. The only thing you should do is to measure the distance between the porosities and to look up their homogenities.


 


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