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- since 1996 -

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Technical Discussions
Norman Thomsen
Norman Thomsen
00:31 Feb-13-2008
AWS D 1.1 UT indication rating, straight probe


Table 6.2 of above standard only gives acceptance/rejection criteria for indications measured with angle probes. How is an indication evaluated when detected and measured with a straight probe? This is relevant for a T-joint.
Thanks,

Norman


 
 Reply 
 
chris s
chris s
02:28 Feb-14-2008
Re: AWS D 1.1 UT indication rating, straight probe
----------- Start Original Message -----------
:
: Table 6.2 of above standard only gives acceptance/rejection criteria for indications measured with angle probes. How is an indication evaluated when detected and measured with a straight probe? This is relevant for a T-joint.
: Thanks,
: Norman
------------ End Original Message ------------


a straight probe ( 0 degree) is not used for inspection of welds per AWS D1.1 the only thing that it is used for is your lamination examination prior to angle beam scanning. that is why there is no accept/reject criteria. the inspection of a t-joint from the "c" face would be performed with an angle beam.



 
 Reply 
 
Norman Thomsen
Norman Thomsen
02:56 Feb-21-2008
Re: AWS D 1.1 UT indication rating, straight probe
----------- Start Original Message -----------
: :
: : Table 6.2 of above standard only gives acceptance/rejection criteria for indications measured with angle probes. How is an indication evaluated when detected and measured with a straight probe? This is relevant for a T-joint.
: : Thanks,
: : Norman
:
: a straight probe ( 0 degree) is not used for inspection of welds per AWS D1.1 the only thing that it is used for is your lamination examination prior to angle beam scanning. that is why there is no accept/reject criteria. the inspection of a t-joint from the "c" face would be performed with an angle beam.
------------ End Original Message ------------


Chris, thanks for your reply.
I don't agree with your statement, that an angle probe should be used from face C. It makes sense to use a straight probe, and the standard even specifies use of an angle perpendicular to the fusion line. Use of a straight probe from face C is a very good technique, but i believe the standard should specify rating criteria for this technique. A comment from AWS would be helpful.
Thanks,
Norman



 
 Reply 
 
John O'Brien
Consultant, -
Chevron ETC , USA, Joined Jan 2000, 280

John O'Brien

Consultant, -
Chevron ETC ,
USA,
Joined Jan 2000
280
03:54 Feb-21-2008
Re: AWS D 1.1 UT indication rating, straight probe
----------- Start Original Message -----------
: : :
: : : Table 6.2 of above standard only gives acceptance/rejection criteria for indications measured with angle probes. How is an indication evaluated when detected and measured with a straight probe? This is relevant for a T-joint.
: : : Thanks,
: : : Norman
: :
: : a straight probe ( 0 degree) is not used for inspection of welds per AWS D1.1 the only thing that it is used for is your lamination examination prior to angle beam scanning. that is why there is no accept/reject criteria. the inspection of a t-joint from the "c" face would be performed with an angle beam.
:
: Chris, thanks for your reply.
: I don't agree with your statement, that an angle probe should be used from face C. It makes sense to use a straight probe, and the standard even specifies use of an angle perpendicular to the fusion line. Use of a straight probe from face C is a very good technique, but i believe the standard should specify rating criteria for this technique. A comment from AWS would be helpful.
: Thanks,
: Norman
------------ End Original Message ------------

This issue is not new and the original comment by Chris has validity in that AWS D1.1 does not outline a sceanario where the accept/reject decison would be made solely on the use of a straight beam scan. hence there is no specific reference to it in the code.

I have run into this issue numerous times where no angle beam access is possible. As such you need to design an acceptance criteria based on the loading of the structure and the guidance in the document that then ensures fitness for purpose. It then becomes a client specification.

The alternative is to draft a technical inquiry to AWS requesting a future amendment to code.



 
 Reply 
 
theo micottis
theo micottis
06:32 Feb-21-2008
Re: AWS D 1.1 UT indication rating, straight probe
----------- Start Original Message -----------
Hello, I think straight probe is helpful to characterize type of indication.From face C you can immediately characterize slag or lack of fusion if you have any doubt


 
 Reply 
 
David J. Reid
David J. Reid
00:33 Jul-25-2008
Re: AWS D 1.1 UT indication rating, straight probe
From what I have observed, which is from the ASME code side of the house, it is accepted standard practice when performing "soundness" examinations (using a 0 degree transducer to look for cracks) you set the back refelection from the part being examed at 8 on the horiziontal scale and adjust the gain to get 100 percent FSH. Any indication that has an amplitude of 20 percent or more and / or if there is a total loss of the back refection is cause for reject.

Problem is you won't find that in the ASME code. However if you were to take a basic ASME non-piping cal block you can see where it makes sense. Once you get 100 percent FSH on the defect free part of the block, put it above the 3/4 T hole. The amplitude from it is about 20 percent.

----------- Start Original Message -----------
: : : :
: : : : Table 6.2 of above standard only gives acceptance/rejection criteria for indications measured with angle probes. How is an indication evaluated when detected and measured with a straight probe? This is relevant for a T-joint.
: : : : Thanks,
: : : : Norman
: : :
: : : a straight probe ( 0 degree) is not used for inspection of welds per AWS D1.1 the only thing that it is used for is your lamination examination prior to angle beam scanning. that is why there is no accept/reject criteria. the inspection of a t-joint from the "c" face would be performed with an angle beam.
: :
: : Chris, thanks for your reply.
: : I don't agree with your statement, that an angle probe should be used from face C. It makes sense to use a straight probe, and the standard even specifies use of an angle perpendicular to the fusion line. Use of a straight probe from face C is a very good technique, but i believe the standard should specify rating criteria for this technique. A comment from AWS would be helpful.
: : Thanks,
: : Norman
: This issue is not new and the original comment by Chris has validity in that AWS D1.1 does not outline a sceanario where the accept/reject decison would be made solely on the use of a straight beam scan. hence there is no specific reference to it in the code.
: I have run into this issue numerous times where no angle beam access is possible. As such you need to design an acceptance criteria based on the loading of the structure and the guidance in the document that then ensures fitness for purpose. It then becomes a client specification.
: The alternative is to draft a technical inquiry to AWS requesting a future amendment to code.
------------ End Original Message ------------




 
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