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Technical Discussions
Anandh Perumal
India, Joined Jan 2015, 19

Anandh Perumal

India,
Joined Jan 2015
19
08:22 May-14-2018
Defect depth location in Radiography

How to identify defect depth location in Radiography?Like near cover,middle or root

 
 Reply 
 
S V Swamy
Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex , India, Joined Feb 2001, 787

S V Swamy

Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
787
09:27 May-14-2018
Re: Defect depth location in Radiography
In Reply to Anandh Perumal at 08:22 May-14-2018 (Opening).

One can make a rough estimate by studying the sharpness of the discontinuity....one closer to the film will be sharpest, one in the middle less sharp and one closer to the top (source) will be most unsharp (of course, even that will be within acceptable limits otherwise, the radiograph will not be accepted for evaluation.

To get a more precise information of the depth, two shots are needed and the depth can be calculated using the triangulation technique.

 
 Reply 
 
Anandh Perumal
India, Joined Jan 2015, 19

Anandh Perumal

India,
Joined Jan 2015
19
11:02 May-14-2018
Re: Defect depth location in Radiography
In Reply to S V Swamy at 09:27 May-14-2018 .

Thanks for your reply sir.but what you mean is, unless two or three defects of different sharpness are available in the same film it is difficult to estimate the location provided the particular wire of the penetrameter is visible.the doubt is in double wall single image in pipes of dia 6"

 
 Reply 
 
Dr. Uwe Zscherpel
Director,
BAM Berlin, Germany, Joined Jan 2010, 83

Dr. Uwe Zscherpel

Director,
BAM Berlin,
Germany,
Joined Jan 2010
83
19:15 May-14-2018
Re: Defect depth location in Radiography
In Reply to Anandh Perumal at 11:02 May-14-2018 .

The depth information is lost by the radiographic projection technique onto an imaging plane. To discover this indfo again you have to use several projection angles. The simplest what you can do is called Stereo radiography using only two different projection angles. For the different position shift of the indications in different depths you can recover their position in depth. If you use more angles up to 200 it is called Laminography ad if you use thousend angles in 360 degree it is called computed tomography CT.
Uwe Z.

1
 
 Reply 
 
ismail
NDT Inspector, TOFD and PAUT Specialist
Turkey, Joined Oct 2008, 24

ismail

NDT Inspector, TOFD and PAUT Specialist
Turkey,
Joined Oct 2008
24
14:00 May-15-2018
Re: Defect depth location in Radiography
In Reply to Anandh Perumal at 08:22 May-14-2018 (Opening).

Hi Anandh

Triangulation Technique used to determine flaw depth in an object has been explained T.O.33B-1-1 Par.6.4.17.2.3 Page 6-109.
Could you please look at http://www.tinker.af.mil/Portals/106/Documents/Technical%20Orders/AFD-101516-33B-1-1.pdf

İsmail KAHVECİOĞLU
NDT L3

1
 
 Reply 
 
Michel Couture
NDT Inspector,
consultant, Canada, Joined Sep 2006, 869

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
869
20:56 May-16-2018
Re: Defect depth location in Radiography
In Reply to ismail at 14:00 May-15-2018 .

I am curious as to why you would like to locate the depth of a defect using radiography when ultrasounds examination would give you the information almost instantly?

 
 Reply 
 
Michel Couture
NDT Inspector,
consultant, Canada, Joined Sep 2006, 869

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
869
21:45 May-16-2018
Re: Defect depth location in Radiography
In Reply to ismail at 14:00 May-15-2018 .

I am curious as to why you would like to locate the depth of a defect using radiography when ultrasounds examination would give you the information almost instantly?

 
 Reply 
 
Anandh Perumal
India, Joined Jan 2015, 19

Anandh Perumal

India,
Joined Jan 2015
19
05:46 May-17-2018
Re: Defect depth location in Radiography
In Reply to Michel Couture at 21:45 May-16-2018 .

Mr Michel,These are for boiler pipes of thickness 7mm to 16mm where we need some permanent record for submission to IBR Inspectors for approval which manual UT lacks.as you know in boilers, tubes and pipes will be there. PAUT in tubes are not satisfactory last time(the defects or reworks are more in PAUT than RT.) so we gave contract to one RT agency so that they can handle pipes and tubes.
Why we need depth?for defect rectification and when we discuss defects with welders they will ask the location whether is it root(GTAW) or fill pass(SMAW).

 
 Reply 
 
Shane Feder
, Quality Co-ordinator (SubSea)
Thailand, Joined Dec 2014, 89

Shane Feder

, Quality Co-ordinator (SubSea)
Thailand,
Joined Dec 2014
89
06:15 May-21-2018
Re: Defect depth location in Radiography
In Reply to Anandh Perumal at 05:46 May-17-2018 .

Anandh,
A competent interpreter should be able to tell you pretty easily approximate depth.
I am presuming it is a single vee joint configuration.
The three main defects you will see are lack of root fusion, lack of sidewall fusion and/or slag inclusion.
Due to internal root protusion the actual root is "usually" pretty easy to see.
A single or double straight line on the edge of the root will be a GTAW root defect.
Based on the single vee configuration any other defects will be SMAW fill defects and the further they are away from the root the closer they are to the surface.
The only other scenario could possibly be slag between the GTAW and SMAW layers but if it is slag it will only require partial excavation down to the GTAW metal anyway.
Hope that helps,
Cheers,
Shane

1
 
 Reply 
 
Anandh Perumal
India, Joined Jan 2015, 19

Anandh Perumal

India,
Joined Jan 2015
19
07:50 May-21-2018
Re: Defect depth location in Radiography
In Reply to Shane Feder at 06:15 May-21-2018 .

Mr Shane,Thanks for your reply.agreed with all your points.but my doubt is not yet cleared.the root penetration is good. there is no straight line (GTAW).but there is a continuous curved line throughout the length above that . intepreter's view is lack of fusion.these are welded by qualified welders who will never do this type of mistakes and the job is done continuously without break.only three passes root pass,hot pass(GTAW) and final(SMAW) in the whole job so possibilities are also less.i grounded the reinforcement and did RT again same line is present in that too.kindly suggest.

 
 Reply 
 
Shane Feder
, Quality Co-ordinator (SubSea)
Thailand, Joined Dec 2014, 89

Shane Feder

, Quality Co-ordinator (SubSea)
Thailand,
Joined Dec 2014
89
04:14 May-22-2018
Re: Defect depth location in Radiography
In Reply to Anandh Perumal at 07:50 May-21-2018 .

Anandh,
Without seeing the graphs it is very hard to comment.
1 What diameter ?
2 What thickness ? (you say 7-16 mm - are you getting defects on all thicknesses)
3 Are they being shot DWSI or DWDI ?
5 What position are they welded in ? - this is probably the most critical when trying to ascertain the reason for a defect.
Regards,
Shane

1
 
 Reply 
 
Shane Feder
, Quality Co-ordinator (SubSea)
Thailand, Joined Dec 2014, 89

Shane Feder

, Quality Co-ordinator (SubSea)
Thailand,
Joined Dec 2014
89
04:56 May-22-2018
Re: Defect depth location in Radiography
In Reply to Shane Feder at 04:14 May-22-2018 .

Anandh,
Further questions
1 Are you getting this problem with 1 x welder or multiple welders ?
2 Is the curved line touching the edge of the root or is there a gap between ?

It is my personal opinion (based on 14 yrs pipe-welder/16 years CWI) that three runs is insufficient and may "possibly" be the cause of your problems.
The capping run is basically a quick wash on the surface to add additional reinforcement.
All the work should be done prior to this with a hot as possible fill layer (or layers).
If the weld is completed without break as you stated the amps would be turned down slightly for the final capping run.
Based on your comments your welders are filling & capping in one run and that may be leading to slag / LOF issues between the GTAW & SMAW layers.

Best idea is for you or a competent CWI to supervise the careful excavation of one of the welds and the instant the welder locates any dark indication they are to pause and allow the supervisor to inspect.
If it is slag it will be very easy for the welder to see and follow during further excavation.

Dependent on code you are using if you can prove to the RT interpreter that it is a slag inclusion and not LOF the weld may be acceptable and not rejectable.
Hope that helps,
Regards,
Shane

1
 
 Reply 
 
Anandh Perumal
India, Joined Jan 2015, 19

Anandh Perumal

India,
Joined Jan 2015
19
07:43 May-23-2018
Re: Defect depth location in Radiography
In Reply to Shane Feder at 04:56 May-22-2018 .

Mr Shane,Thanks for sharing your knowledge. DiameterxThickness 168.28mmx7.11mm,DWSI,5G Position
Multiple welders,Root completely fused.after root which of smaller width (approx 7mm) the fill and cover pass of SMAW,which is wider than root(width approx 24mm) l curved lines with width more than 1mm are visible on both sides of root.
Do you mean to say that lines due to difference in amps used for GTAW(ER 70S2,Dia 2.4mm) and SMAW (E7018,Dia 3.15mm)
Have you noticed slag as continuous curved line too in cases like this.

 
 Reply 
 
Shane Feder
, Quality Co-ordinator (SubSea)
Thailand, Joined Dec 2014, 89

Shane Feder

, Quality Co-ordinator (SubSea)
Thailand,
Joined Dec 2014
89
12:55 May-23-2018
Re: Defect depth location in Radiography
In Reply to Anandh Perumal at 07:43 May-23-2018 .

Sorry Anandh,
I have given you as much help as I can.
All I suggest is you get a "tracing" from the RT interpreter and carefully excavate one of the rejected welds.
That is the only way you will find out what your problem is.
Or, get UT done and get the RT and UT techs to discuss and see what the problem is.
Cheers,
Shane

1
 
 Reply 
 
collin Maloney
NDT Inspector, - Plant Inspector
Applus RTD, Australia, Joined Nov 2000, 147

collin Maloney

NDT Inspector, - Plant Inspector
Applus RTD,
Australia,
Joined Nov 2000
147
07:18 May-24-2018
Re: Defect depth location in Radiography
In Reply to Shane Feder at 12:55 May-23-2018 .

suggest you take a look at following link, very hard for anyone to make a call without seeing the graphs. My first impression is wagon tracks if only 3 runs. Between fill and cap. If filling approx. 5mm in one run, probably lots of heat input and side wall undercut.

https://www.nde-ed.org/EducationResources/CommunityCollege/Radiography/TechCalibrations/RadiographInterp.php

1
 
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