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Technical Discussions
xiaohuozi
xiaohuozi
03:42 Dec-20-2008
Aws d1.1 UT Indication rate

may you tell how to define "b" of a-b-c=d of UT indication rate in AWS D1.1? Thanks.


    
 
 
Ed T.
Ed T.
04:14 Dec-21-2008
Re: Aws d1.1 UT Indication rate
----------- Start Original Message -----------
: may you tell how to define "b" of a-b-c=d of UT indication rate in AWS D1.1? Thanks.
------------ End Original Message ------------

b is your dB level at reference. In other words when you set your 0.060" diameter hole in the IIW block to say 80% FSH and your dB level is 50dB, then 50 becomes b.


    
 
 
MEHDY
MEHDY
02:50 Dec-24-2008
Re: Aws d1.1 UT Indication rate
----------- Start Original Message -----------
: : may you tell how to define "b" of a-b-c=d of UT indication rate in AWS D1.1? Thanks.
: b is your dB level at reference. In other words when you set your 0.060" diameter hole in the IIW block to say 80% FSH and your dB level is 50dB, then 50 becomes b.
------------ End Original Message ------------




    
 
 
Kenneth
Kenneth
13:59 Aug-27-2009
Re: Aws d1.1 UT Indication rate
In Reply to MEHDY at 02:50 Dec-24-2008 .

Accordance to AWS D1.1 2008 "b" have to be between 40 and 60 %, not 80%

    
 
 
Roger Duwe
NDT Inspector, API-510, 570, 653
MISTRAS, USA, Joined Jan 2009, 148

Roger Duwe

NDT Inspector, API-510, 570, 653
MISTRAS,
USA,
Joined Jan 2009
148
15:46 Sep-02-2009
Re: Aws d1.1 UT Indication rate
In Reply to Kenneth at 13:59 Aug-27-2009 .

"b" is the dB level that you are using to put the response peak from the reference hole -- .060" dia. -- exactly on your marked Reference line. Refrence is traditionally 80% Full Screen Height, but any level works. The "between 40 and 60%" doesn't change the equation. "b" will always be the dB it takes to put the reference indication exactly on your chosen Reference line. It should be expressed to a 1/10th of a dB accuracy. "52.8 dB"

    
 
 
john
john
17:08 Sep-02-2009
Re: Aws d1.1 UT Indication rate
In Reply to Roger Duwe at 15:46 Sep-02-2009 .

per AWS D1.1, reference level "B" is not traditionally 80% FSH, 50% FSH is most widely used.
80% FSH is used for ASME inspection for the 1st point in the DAC.
Assume 50% is ref.(A=indication dB @ 50%; B=ref. Db; C=attenuation;D=ind. rating)
(A-B-C=D)

    
 
 
P V SASTRY
R & D, NDT tecniques metallurgy
TAKEN VRS FROM THE POSITION OF SR. DEPUTY GENERAL MANAGER BHEL CORPORATE R&D, India, Joined Jan 2003, 195

P V SASTRY

R & D, NDT tecniques metallurgy
TAKEN VRS FROM THE POSITION OF SR. DEPUTY GENERAL MANAGER BHEL CORPORATE R&D,
India,
Joined Jan 2003
195
12:08 Sep-07-2009
Re: Aws d1.1 UT Indication rate
In Reply to john at 17:08 Sep-02-2009 .

Dear Sir,

You may be right that traditionally 50% of FSH is used for fixing the reference db level ‘B’.

But how does it matter if 50 to 75% (as I have learned from an authentic source a few years back) or even 80% of FSH is used as reference level (for ‘B’) since it is only an arbitrary reference and the subsequent measurements are only relative to it.
Sorry I like to break free of tradition if there is latitude.

With best wishes

P V SASTRY

    
 
 
Michel Couture
NDT Inspector,
consultant, Canada, Joined Sep 2006, 834

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
834
20:38 Sep-07-2009
Re: Aws d1.1 UT Indication rate
In Reply to P V SASTRY at 12:08 Sep-07-2009 .

I hesitated in commenting on this subject because I don't have a recent copy of D1.1 available. But I consulted the CSA W59 which is the Canadian adaptation of the AWS D1.1 (I was told by some people sitting on the Canadian comitee that it is identical) and found in the paragraph related to calibration for Angle Beam examination states that the Horizontal Level shall be between 50% and 75% of the maximum readable level of vertical indication (vertical limit).

When I started doing weld inspection, I used to calibration my screen to maximum sensitivity. But, a friend told me that I should calibrate for minimum sensitivity. The reason given to me was that if you calibrate for maximum, you will end up with a lot of grass on your screen when you add your Scanning Level dB, specially with the longer Sound Path Distances.

So keeping the 0.060" hole at 50% FSH makes a lot of sense.

    
 
 
john
john
15:00 Sep-08-2009
Re: Aws d1.1 UT Indication rate
In Reply to P V SASTRY at 12:08 Sep-07-2009 .

MY conclusion would be that if you are making 80% FSH your ref. then you probably have never actually scanned at the bare minimum of 14dB over ref. There is too much hash at 50% let alone 80%.
The word "shall" does not provide "latitude".

    
 
 
jason
jason
06:40 Oct-14-2009
Re: Aws d1.1 UT Indication rate
In Reply to xiaohuozi at 03:42 Dec-20-2008 (Opening).

Just to make things more confusing, some modern machines with the AWS program built in require an 80% FSH setting of the 0.060" hole to work. Do the manufacturers know something
we don't?

    
 
 
john
john
22:21 Oct-15-2009
Re: Aws d1.1 UT Indication rate
In Reply to jason at 06:40 Oct-14-2009 .

some of the new machines that you are refering to also only give the final "D" rating without giving you the A, B, or C for the report. So getting the "D" rating doesn't really do any good if you still have to break out the calculator to do the math.
The 80% sounds like a progamming flaw carried over from somebody familiar only with ASME code.

    
 
 
Maneesh Narayanan
Maneesh Narayanan
10:17 Jan-09-2012
Re: Aws d1.1 UT Indication rate
In Reply to xiaohuozi at 03:42 Dec-20-2008 (Opening).

can u please define"a" & "c" of a+b+c=d ut indication rate in awsD1.1? Thanks....??

    
 
 
Shahid Bangash
Engineering,
Saudi Arabia, Joined Feb 2009, 132

Shahid Bangash

Engineering,
Saudi Arabia,
Joined Feb 2009
132
08:37 Jan-10-2012
Re: Aws d1.1 UT Indication rate
In Reply to jason at 06:40 Oct-14-2009 .

HI Jason
Which modern machines with the AWS program built in require an 80% FSH setting of the 0.060" hole to work ?

    
 
 
Ali
Director, Technical manager, NDT Level III
3T, Iran, Joined Nov 2011, 30

Ali

Director, Technical manager, NDT Level III
3T,
Iran,
Joined Nov 2011
30
14:35 Jan-16-2012
Re: Aws d1.1 UT Indication rate
In Reply to Kenneth at 13:59 Aug-27-2009 .

AWS D1.1 2010 also

    
 
 
Michael Fitzpatrick
Michael Fitzpatrick
18:17 Jan-17-2012
Re: Aws d1.1 UT Indication rate
In Reply to xiaohuozi at 03:42 Dec-20-2008 (Opening).

I would refer to page 325 of D1.1 if you have an older version like the 2002/August 2004 version on file. it explicitly and in detail explains everything; however, it is true that in regards to DB level there should be some room left open for variables such as the metal's internal structure which can severely affect the decibel level required.

    
 
 
Omar Hernandez
NDT Inspector, Quality Engineer
Quality control at Caterpillar Mex., Mexico, Joined Jan 2012, 1

Omar Hernandez

NDT Inspector, Quality Engineer
Quality control at Caterpillar Mex.,
Mexico,
Joined Jan 2012
1
23:54 Jan-19-2012
Re: Aws d1.1 UT Indication rate
In Reply to Ed T. at 04:14 Dec-21-2008 .

By the way, the AWS D1.1 2010 is askind for 60% FSH, is not longer at 80%.

Reagards...

    
 
 
John
John
15:50 Jan-20-2012
Re: Aws d1.1 UT Indication rate
In Reply to Omar Hernandez at 23:54 Jan-19-2012 .

FSH range is 40% to 60%, i dont believe it was ever 80% FSH

    
 
 
lalbabu kushwaha
lalbabu kushwaha
18:50 Jan-23-2012
Re: Aws d1.1 UT Indication rate
In Reply to xiaohuozi at 03:42 Dec-20-2008 (Opening).

ndt u.t acipt standar aws d1.1

    
 
 
Oliviero
NDT Inspector,
Quality Control srl, Italy, Joined Oct 2008, 414

Oliviero

NDT Inspector,
Quality Control srl,
Italy,
Joined Oct 2008
414
21:37 Jan-24-2012
Re: Aws d1.1 UT Indication rate
In Reply to Maneesh Narayanan at 10:17 Jan-09-2012 .

Download

I simulate an UT examination of a butt weld Cyclically loaded.
Attached there is the explanation step by step of the AWS D1.1 2010 ed. requirements, starting from the axes references, the scanning plan, the system calibration with a 70° search unit, the scanning sensitivity setting, and a discontinuity evaluation with using a, b, c and d.
    
 
 
yasin
Turkey, Joined Jun 2011, 20

yasin

Turkey,
Joined Jun 2011
20
13:11 Jan-25-2012
Re: Aws d1.1 UT Indication rate
In Reply to Oliviero at 21:37 Jan-24-2012 .

Oliviero ;
really good working. congratulate you. it is perfect.

So coming to table 6,3
30 mm thickness and lets say class B for evaluations.
12 dB indication rate is not accepted. is it true ?

    
 
 
Csaba Hollo
,
Retired, Canada, Joined Feb 2010, 301

Csaba Hollo

,
Retired,
Canada,
Joined Feb 2010
301
23:54 Jan-25-2012
Re: Aws d1.1 UT Indication rate
In Reply to yasin at 13:11 Jan-25-2012 .

Very good description from Oliviero, except for transducer sizing.
6.22.7.2 - The transducer crystal shall be square or rectangular in shape and may vary from 5/8 in to 1 in [15 mm to 25 mm] in width and from 5/8 in to 13/16 in [15 mm to 20 mm] in height (see Figure 6.17). The maximum width to height ratio shall be 1.2 to 1.0, and the minimum width-to-height ratio shall be 1.0 to 1.0.

Therefore, the 13 x 13 mm transducer specified in the drawing is not in accordance with AWS.

Also with respect to the description of indication rating, any rating positive of '0' must be reported as +, therefore, in Oliviero's example, the indication rating would be +12. From the table 6.3, 30 mm thick material, Class B reflector, this indication rating would be acceptable.
Although not seemingly logical, the lower number rating signifies a more severe reflector.
You have to go back to how the rating was calculated to make sense of this.

    
 
 
Csaba Hollo
,
Retired, Canada, Joined Feb 2010, 301

Csaba Hollo

,
Retired,
Canada,
Joined Feb 2010
301
00:48 Jan-26-2012
Re: Aws d1.1 UT Indication rate
In Reply to yasin at 13:11 Jan-25-2012 .

Very good description from Oliviero, except for transducer sizing.
6.22.7.2 - The transducer crystal shall be square or rectangular in shape and may vary from 5/8 in to 1 in [15 mm to 25 mm] in width and from 5/8 in to 13/16 in [15 mm to 20 mm] in height (see Figure 6.17). The maximum width to height ratio shall be 1.2 to 1.0, and the minimum width-to-height ratio shall be 1.0 to 1.0.

Therefore, the 13 x 13 mm transducer specified in the drawing is not in accordance with AWS.

Also with respect to the description of indication rating, any rating positive of '0' must be reported as +, therefore, in Oliviero's example, the indication rating would be +12. From the table 6.3, 30 mm thick material, Class B reflector, this indication rating would be acceptable.
Although not seemingly logical, the lower number rating signifies a more severe reflector.
You have to go back to how the rating was calculated to make sense of this.

    
 
 
Shahid Bangash
Engineering,
Saudi Arabia, Joined Feb 2009, 132

Shahid Bangash

Engineering,
Saudi Arabia,
Joined Feb 2009
132
05:35 Jan-26-2012
Re: Aws d1.1 UT Indication rate
In Reply to Csaba Hollo at 00:48 Jan-26-2012 .

Dear All
These Width and height ranges were also confusing me as AWS stating the ranges 5/8 in to in [15 mm to 25 mm] in width and from 5/8 in to 13/16 in [15 mm to 20 mm] in height "MAY BE USED" Shouldn't it be "SHALL BE USED if these are considered obligatory. These dimensions can be deviated from but the W/H ratio and shape of transducer shall conform to the standard.

    
 
 
Oliviero
NDT Inspector,
Quality Control srl, Italy, Joined Oct 2008, 414

Oliviero

NDT Inspector,
Quality Control srl,
Italy,
Joined Oct 2008
414
15:24 Jan-26-2012
Re: Aws d1.1 UT Indication rate
In Reply to yasin at 13:11 Jan-25-2012 .

Yasin,
coming to table 6.3 for 30 mm thickness an indication rate of 12 dB is a class D and it shall be accepted regardless of length or location in the weld.

    
 
 
yasin
Turkey, Joined Jun 2011, 20

yasin

Turkey,
Joined Jun 2011
20
15:38 Jan-26-2012
Re: Aws d1.1 UT Indication rate
In Reply to Oliviero at 15:24 Jan-26-2012 .

Oliviero ;
Before I mention class B but lets dont think about dimension now.

Think Class A ( regardless of length ) = +8 &lower is criteria.

+12 db and 30 mm thickness is it accepted or not.

    
 
 
Oliviero
NDT Inspector,
Quality Control srl, Italy, Joined Oct 2008, 414

Oliviero

NDT Inspector,
Quality Control srl,
Italy,
Joined Oct 2008
414
15:39 Jan-26-2012
Re: Aws d1.1 UT Indication rate
In Reply to Shahid Bangash at 05:35 Jan-26-2012 .

Shahid Bangash and Csaba Hollo,
I think that your obsevations are right. The AWS D1.1 use the term "shall" for the square or rectangular shape, and it use the term "may" for the size crystal range.
But the term "may" could be intended in two manners:
1) as the possibility to use the size included into the range
2)as a prohibition to exceed that range.
The discussion is open.
Probabily the option 2) should be used and the 13x13 mm is wrong. But do you know a search unit with a crystal lesser than 20x22 which could be used on thickness lesser than 30 mm working with good resolution and the adequate energy to work at the amplification required to the code?
Do you have an answer?

    
 
 
Oliviero
NDT Inspector,
Quality Control srl, Italy, Joined Oct 2008, 414

Oliviero

NDT Inspector,
Quality Control srl,
Italy,
Joined Oct 2008
414
21:24 Jan-26-2012
Re: Aws d1.1 UT Indication rate
In Reply to yasin at 15:38 Jan-26-2012 .

Yasin,
+12 db and 30 mm thickness is accepted

    
 
 
Csaba Hollo
,
Retired, Canada, Joined Feb 2010, 301

Csaba Hollo

,
Retired,
Canada,
Joined Feb 2010
301
21:03 Jan-30-2012
Re: Aws d1.1 UT Indication rate
In Reply to Oliviero at 15:39 Jan-26-2012 .

Oliviero, this is one of the biggest problems that I have with this code, and it's sister code in Canada, namely CSA W59, although we are not tied to the transducer size as tightly in the CSA code.

The biggest issue is that the code requires no less than a 15 x 15 mm 70 degree search unit (many use a 19w x 15h mm search unit!) at 2.25 Mhz to perform angle beam examination on as thin as 8mm steel. It is very easy to see that there will be an incredible oversensitivity due to the total saturation of the material with sound, with inherent errors in placement of indications due to the huge wavefront.

You have to see this with Schilerien photography to see how crazy it is. When changed to 5 Mhz, the beam is more predictable, and indications are placed and sized with more accuracy.

I am going to take my QA Rep hat off and admit to using alternative transducers for flaw placement and length characterization, but for the dB rating scheme, once I have determined that it is a relevant indication and not a backing bar or geometry reflector (with alternative methods), I use the AWS probes for this calculation. The reason I do this is that I have ground out welds myself, to find absolutely nothing at all, and upon retesting, the original indication remains.

    
 
 
yasin
Turkey, Joined Jun 2011, 20

yasin

Turkey,
Joined Jun 2011
20
14:15 Feb-07-2012
Re: Aws d1.1 UT Indication rate
In Reply to Csaba Hollo at 21:03 Jan-30-2012 .

what do you say about.
6.26.6.5 indication rating :
Instrument with gain in dB
a-b-c=d
Instrument with attenuation in dB
b-a-c= d

how is difference calculation ?

and other question is ; up to 38 mm thickness;A:W:S does not contain 45 and 60 angle probe. There is just 70 degree angle prob scanning. Table 6,3 why ?

    
 
 
Oliviero
NDT Inspector,
Quality Control srl, Italy, Joined Oct 2008, 414

Oliviero

NDT Inspector,
Quality Control srl,
Italy,
Joined Oct 2008
414
22:06 Feb-08-2012
Re: Aws d1.1 UT Indication rate
In Reply to yasin at 14:15 Feb-07-2012 .

Yasin,

The difference between the two formulas is for use of different ultrasonic instruments as wrote below
Instrument with GAIN in dB
a-b-c=d
Instrument with ATTENUATION in dB
b-a-c= d
Really I don't know any type of industrial equipment which has the scale of the "attenuator" instead of the "Gain", but it could be that some equipment could have the dB regulation from high dB number to low dB number corresponding to the increasing of the echo height on the screen. In this case the second formula need to be used.
About the second question "up to 38 mm thickness;A:W:S does not contain 45 and 60 angle probe. There is just 70 degree angle prob scanning. Table 6,3 why ?" I have the same doubt, but it is not prohibited to use more angles.

    
 
 
yasin
Turkey, Joined Jun 2011, 20

yasin

Turkey,
Joined Jun 2011
20
09:18 Feb-09-2012
Re: Aws d1.1 UT Indication rate
In Reply to Oliviero at 22:06 Feb-08-2012 .

Oliviero ,
it is not prohibited to use more angles. But how is the accept-reject critireia
for 45 or 60 degree prob for lower 38 mm thickness.
have you got any idea ?

    
 
 
john
john
19:51 Feb-09-2012
Re: Aws d1.1 UT Indication rate
In Reply to yasin at 09:18 Feb-09-2012 .

You cannot base accept or reject criteria off of additional angle used, only the 70-deg in this case, the additional angle can be used to verify flaw type and location and sizing.
This is much like using the 0-deg on face C on tee connections (no criteria for rejection with 0-deg)

    
 
 
Oliviero
NDT Inspector,
Quality Control srl, Italy, Joined Oct 2008, 414

Oliviero

NDT Inspector,
Quality Control srl,
Italy,
Joined Oct 2008
414
21:09 Feb-09-2012
Re: Aws d1.1 UT Indication rate
In Reply to yasin at 09:18 Feb-09-2012 .

Yasin,
for thicknesses up to 25 mm I would use once the 70 degree. For thicknesses from 26 mm to 38 mm I would add at least an angle as much as perpendicular to the weld edge preparation (e.g. as per Note F into the Legenda) and I would use the same reference sensitivity method and apply the most stringent value. This in fabrication could be conservative but not too expensive.

    
 
 
syedajeez
NDT Inspector,
scaanray metallurgical services, India, Joined Jan 2012, 9

syedajeez

NDT Inspector,
scaanray metallurgical services,
India,
Joined Jan 2012
9
03:29 Aug-15-2012
Re: Aws d1.1 UT Indication rate
In Reply to Oliviero at 21:37 Jan-24-2012 .

the pdf file was excelent , do you have accepance chart. for aws d1.1

    
 
 
Csaba Hollo
,
Retired, Canada, Joined Feb 2010, 301

Csaba Hollo

,
Retired,
Canada,
Joined Feb 2010
301
19:44 Aug-15-2012
Re: Aws d1.1 UT Indication rate
In Reply to syedajeez at 03:29 Aug-15-2012 .

Reproducing the chart(s) would be a copyright violation...it is not likely that Rolf will allow it.

    
 
 
Freddy Harmon
Freddy Harmon
19:09 Oct-17-2017
Re: Aws d1.1 UT Indication rate
In Reply to xiaohuozi at 03:42 Dec-20-2008 (Opening).

I've followed the AWS D1.1 procedure while performing UT shearwave inspection calculating the defect rating using the A-B-C=D calculation. I set my ref"B" off of the 0.060" side drilled hole of the IIW Block at 50% of Full Screen Height. While scanning a 2" thick NAVSHIP block I noticed something that gave me pause.

I got a signal from the 0.500" deep side drilled hole that maxed out at 60% FSH and was rejectable Class A indication per Table 6.3 of D1.1.

I then flipped the block over and found the exact same side drilled hole which was now 1.5" deep maxed out at 41% FSH and was Acceptable Class B per Table 6.3.

My conclusion is that attenuation and depth has something to do with the calculation of the D rating. Can anyone give me a little more information on why the same sized indication is rejectable if closer to the surface but rejectable if deeper?

    
 
 
Paul Holloway
Consultant, UT Level 3
Holloway NDT & Engineering Inc , Canada, Joined Apr 2010, 175

Paul Holloway

Consultant, UT Level 3
Holloway NDT & Engineering Inc ,
Canada,
Joined Apr 2010
175
20:13 Oct-17-2017
Re: Aws d1.1 UT Indication rate
In Reply to Freddy Harmon at 19:09 Oct-17-2017 .

What you've discovered is that sound does not attenuate at exactly 2dB per inch. It's merely an estimate.

While the 2dB per inch approximation allows us to use a single reference reflector for calibration, it is not very precise. A DAC/TCG is the more reliable approach.

I wrote an article in the CINDE journal regarding this. See May/June this year, Vol. 38 No. 3.

http://www.hollowayndt.com/published-articles/

D1.1 and D1.5 have Annexes for use of a DAC.

    
 
 
Freddy Harmon
Freddy Harmon
20:28 Oct-17-2017
Re: Aws d1.1 UT Indication rate
In Reply to Paul Holloway at 20:13 Oct-17-2017 .

I'll check out your article now and share it with my UT techs.
Thank you very much.

Freddy Harmon

    
 
 

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