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Technical Discussions
SABIR HUSSAIN
SABIR HUSSAIN
07:45 May-24-2010
radiography

using gamma ray Ir-192 how much thickness of steel(minimum and maximum) we can do radiography?

 
 Reply 
 
anjafo79
NDT Inspector
Norway, Joined Aug 2009, 204

anjafo79

NDT Inspector
Norway,
Joined Aug 2009
204
14:35 May-24-2010
Re: radiography
In Reply to SABIR HUSSAIN at 07:45 May-24-2010 (Opening).

10 - 40mm approx. recommened in places

beam will go through less or more than that its the quality of the picture that usually matters in x-ray

I shoot both more and less with acceptable results...

 
 Reply 
 
vfq3481
vfq3481
19:19 May-24-2010
Re: radiography
In Reply to SABIR HUSSAIN at 07:45 May-24-2010 (Opening).

Hello Sabir,
Depend of the code used.

 
 Reply 
 
Kamran
Engineering,
United Arab Emirates (UAE), Joined Jun 2009, 21

Kamran

Engineering,
United Arab Emirates (UAE),
Joined Jun 2009
21
13:50 May-29-2010
Re: radiography
In Reply to SABIR HUSSAIN at 07:45 May-24-2010 (Opening).

hello Sabir Hussain
Penetrating ability of Ir-192 ranges from 10~70 mm (min/max) in Steel (as per RT Level-II book NCNDT, Pakistan )

 
 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
09:13 May-30-2010
Re: radiography
In Reply to Kamran at 13:50 May-29-2010 .

While 10 mm is feasible, it is very difficult to get good contrast and detail and achieve the specified sensitivity. ASME code allows radiography using Ir-192 of thickness less than 19 mm (three fourths of an inch) provided the required sensitivity (usually 2-2T hole) is proven. We, as customers were not satisfied and so we specified x-ray radiography for 12 mm thick joints of stainless steel.

Now, portable air-cooled x-ray machines are available at reasonable cost and provide far superior radiographic images.

 
 Reply 
 
vfq3481
vfq3481
18:30 May-30-2010
Re: radiography
In Reply to S.V.Swamy at 09:13 May-30-2010 .

Hello Sabir,
I look at radiography in a particular kind of way.
You can use Ir-192 to radiograph everything. This is one of the advantages of gamma-rays.
Of course you must guarantee minimum image quality, and for that you must try to use the adequate class of films.
For thinner thicknesses probably is best to use Class 2 (Agfa D3 or Kodak M100).
When you work with ASME requirements you should achieve image quality confortably. European Standards is harder but feasable.
But inspectors must be aware that gamma is not X-Ray, and the tolerance should be greater. Normally this is the problem...when the work is from their company the acceptance criteria is wide and this is not correct.
Regards

 
 Reply 
 
Nigel Armstrong
Engineering, - Specialist services
United Kingdom, Joined Oct 2000, 1096

Nigel Armstrong

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1096
13:08 May-31-2010
Re: radiography
In Reply to vfq3481 at 18:30 May-30-2010 .

"...when the work is from their company the acceptance criteria is wide and this is not correct."

vfq3481, how true. How often does one see small bore pipework shot by contact with Ir 192. Lousy radiographs where the only thing that is right is perhaps the density. IQI placed film side tells you absolutely nothing about exposure set-up quality. Skill has been replaced by repetition and get the job done quick. Company RFI's are terrified to reject in case they become the rejects.

At present I am working to ASME code with ToFD and Phased Array. If the customer paid as much attention to procedural quality requirements in gamma radiography as they do to ToFD/PA then suddenly the latter wouldseem so much more attractive.

 
 Reply 
 
Jon Wallis
NDT Inspector, -
Netherlands, Joined Feb 2010, 626

Jon Wallis

NDT Inspector, -
Netherlands,
Joined Feb 2010
626
15:42 May-31-2010
Re: radiography
In Reply to Nigel Armstrong at 13:08 May-31-2010 .

It seems that almost no authority, either notified body or clients rep. seems willing or capable of sentencing radiographs according to quality. As Nigel says, IQI always placed on the film side and incorrect source-to-object distance with DWDI techniques. In Northern Europe we are generally using selenium instead of iridium these days for thinner wall thicknesses but even then, corners are being cut.

Back to the subject - purely from a practical stand point, the maximum thickness of steel that iridium can penetrate and enough radiation will be left over to expose a radiograph is approx. 3" (75mm). The minimum thickness is as thin as you want it to be. This has nothing to do with codes and norms of course.

 
 Reply 
 
vfq3481
vfq3481
20:23 May-31-2010
Re: radiography
In Reply to Nigel Armstrong at 13:08 May-31-2010 .

Hello Nigel and John,
In Portugal it's like third world in NDT.
I represent one of the four NDT Laboratories in Portugal and we are only accredited for the execution in our client facilities. The other three...only one have the requirements to be a full NDT Laboratory. But the other two have the tittle.
We are always facing problems like: the other ones do more in less time or the other ones didn't require access to do that or when the other came we don't have any repairs. And if we start in personnel qualifications and certifications we will be here all day.
Now we have a situation. If it's PED lines/system we call A or B, if not C or D or E. It's sad.

 
 Reply 
 
tj
tj
04:49 Jun-05-2010
Re: radiography
In Reply to Nigel Armstrong at 13:08 May-31-2010 .

While I agree that poor technique choices are abound in RT (as with all methods) I hardly find that this negates in any way its effectiveness in material evaluation or its suppport role for other NDT methods. It just amazes me how all the PA and TOFD fanboys cry to arms anytime RT is mentioned. This is coming from RT III and UT III. So bias I am not.

Thanks,
TJ

 
 Reply 
 
Nigel Armstrong
Engineering, - Specialist services
United Kingdom, Joined Oct 2000, 1096

Nigel Armstrong

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1096
07:05 Jun-05-2010
Re: radiography
In Reply to tj at 04:49 Jun-05-2010 .

tj

Your use of the curious epithet "fanboys" is erroneous and indicates possibly you are not numerate tj as I am the only poster on this thread who mentioned either TOFD or PA.

Hwever in the spirit of forum harmony I'll be happy to follow your chosen links to other forum threads where "fanboys cry to arms anytime RT is mentioned" and commiserate with you tj about the unfairness of it all. If you cannot post such links then I hope you will be the gentleman I am certain you are and withdraw your remark and apologise. But I wont hold my breath waiting for that from an unbiased UT and RT Level III whose forum avatar is a "Radiation Hazard" warning sign!

Have a nice day!

;>D

 
 Reply 
 
tj
tj
16:51 Jun-05-2010
Re: radiography
In Reply to Nigel Armstrong at 07:05 Jun-05-2010 .

My avatar is chosen from the field which I work in (nuclear) not an NDT method. I choose not to continue this road to nowhere. I will not apologize for the remark as you know every bit is true. I was not referring to you exclusively (fanboys being plural). I will, however, apologize for interrupting forum harmony. It does not matter to me the fairness of any of this. It just works against best practice I believe.

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

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
869
19:27 Jun-05-2010
Re: radiography
I don't know about other people and can only speak for myself. I've been a member of this site now for some time and been doing NDT since 1989. First in the aircraft industry because I was in the Air Force and now that I am retired, much of my time is spent in the nuclear and petro-chemical. Yet not a day goes by that I don't learn something new!!!

In my dealing with different people including and specially coworkers who sometimes are less certified then I am, I've learn to ask questions first if I didn't agree with the optic. Some of my coworkers although less certified have many more years of experience than I do in a specific area of NDT and one would be wise to at least listen to them before dismissing them. The same is true in this forum. We come from different walk of life with different expertise. I can't speak for anyone else, but I know that I have gain valuable kowledge from the regular suscribers of this site. One would be foolish to disregard them because we are use to do things a certain way. NDT is an ever changing world and if we want to go forward as technicians we can't say that this is the way it should be done because this is the way we've always done it.

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

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
869
19:23 Jun-06-2010
Re: radiography
In Reply to Michel Couture at 19:27 Jun-05-2010 .

I've reread my post and it reminded me of an anecdote that happened in Toronto, Canada during WW1. We have the Canadian National Exhibition every year. It last for two weeks and used to features the latest as far as farm animals and other things. Well during WW1, they were exhibiting a Model T Ford with a Gun turret and a machine gun trhough its roof. As the Canadian General and his entourage inspected this thing he asked what it was. The builder said that it was a tank. The General replied that war would always be fought on horses.

Now we know it isn't true and as a result we (Canada) have to buy our tanks from Germany and the USA. HUM????

 
 Reply 
 
Rameez
Rameez
22:17 Jun-06-2010
Re: radiography
In Reply to SABIR HUSSAIN at 07:45 May-24-2010 (Opening).

I want to know, while shooting pipe weld for double wall exposure and double wall viewing (not superimposed), IQI (hole type ASME pene) will be based on Single wall thickness or a double wall thickness.
much Appreciated!

 
 Reply 
 
CJ
CJ
09:35 Jun-07-2010
Re: radiography
In Reply to Rameez at 22:17 Jun-06-2010 .

Both of course. You are still shooting through two wall thickness.

 
 Reply 
 
Rameez
Rameez
06:40 Jun-08-2010
Re: radiography
In Reply to CJ at 09:35 Jun-07-2010 .

Hello, Does anyone have any experience writing CGSB RT Level II practical exam?
How would you identify the diffenrce between lack of fusion and Crack, if both are on root pass of the weld.

 
 Reply 
 
Rameez
Rameez
03:58 Jun-09-2010
Re: radiography
In Reply to Rameez at 06:40 Jun-08-2010 .

zoom image



Find attached weld exposure for Steel. I cannot identify the defect in black found inside drop through (Icicle). Is it an elongated porosity? Please comment on it.
 
 Reply 
 
anjafo79
NDT Inspector
Norway, Joined Aug 2009, 204

anjafo79

NDT Inspector
Norway,
Joined Aug 2009
204
10:34 Jun-09-2010
Re: radiography
In Reply to Rameez at 03:58 Jun-09-2010 .

Hi.
One thing about calculating IqI double wall viewing superimposed or elliptical:

Am I missing something as I have been trying to figure out if you calculate using 2 wall thickness or 1. I cant find specific reference in ASME V stating this.

Using 1 wall thickness gives better sensitivity so our level III says just use 1 and refer to the table for IqI wire required.


"Both of course. You are still shooting through two wall thickness." what about contact DWSI??


If its refernced in ASME V please state where.

Thanks.

 
 Reply 
 
Kamran
Engineering,
United Arab Emirates (UAE), Joined Jun 2009, 21

Kamran

Engineering,
United Arab Emirates (UAE),
Joined Jun 2009
21
18:03 Jun-09-2010
Re: radiography
In Reply to Rameez at 06:40 Jun-08-2010 .

Well Rameez
it require a lot of experience and back ground knowledge to distinguish between LOF and Crack in root pass, mostly in my experience this case appers in TIG welding root pass Auto or manual, LOF appears slightly in a stright line with a sharp boundries exactly at root face location, whereas Crack has a weaveness in apperance and u can find a starting and propogation direction
Thanks

 
 Reply 
 
Juan Amado
Engineering, Inspection
Arco Industrial, S.A., Panama, Joined Nov 2001, 44

Juan Amado

Engineering, Inspection
Arco Industrial, S.A.,
Panama,
Joined Nov 2001
44
22:19 Jun-09-2010
Re: radiography
In Reply to Rameez at 22:17 Jun-06-2010 .

As per ASME Section V, IQI selection shall be based on nominal single wall thickness plus weld reinforcement or if the welds are ground flush just the single wall thickness.

In calculating your Ug for such a shot (Double exposure, double viewing) however, you have to take into account the outside diameter of the pipe as your subject thickness. If you don't, the image of the weld that is farthest from the film will be blurred.

Hope this helps

 
 Reply 
 
anjafo79
NDT Inspector
Norway, Joined Aug 2009, 204

anjafo79

NDT Inspector
Norway,
Joined Aug 2009
204
10:53 Jun-10-2010
Re: radiography
In Reply to Juan Amado at 22:19 Jun-09-2010 .

thank juan thats exactly how we do it.

 
 Reply 
 
Drive
Drive
17:53 Jun-10-2010
Re: radiography
In Reply to Rameez at 03:58 Jun-09-2010 .

Rameez,

Please what kind of weld is indicated in that film picture?

 
 Reply 
 
Rameez
Rameez
23:05 Jun-10-2010
Re: radiography
In Reply to Drive at 17:53 Jun-10-2010 .

Its the fusion weld in the picture you see.

 
 Reply 
 
shankar
shankar
18:54 Feb-21-2012
Re: radiography
In Reply to SABIR HUSSAIN at 07:45 May-24-2010 (Opening).

can you tell me that"what is the min.and max. thickness can be taken in iridium-192.

 
 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
09:06 Feb-22-2012
Re: radiography
In Reply to Rameez at 03:58 Jun-09-2010 .

this looks like excess penetration with localised suck back where the welder has failed to control the molten puddle in the root run.,The darker centre is where the puddle has sucked up, a bit like an upside down volcano. Probably best described as vertical piping porosity. I would look at its density compared to the parent material before making a call

 
 Reply 
 
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
21:54 Feb-22-2012
Re: radiography
In Reply to collin maloney at 09:06 Feb-22-2012 .

Dear Sir,
You are very much right about it.
The black spots are the shrinkage cavities formed inside the metallic globules created due to excessive penetration
Excessive penetration can happen during welding, particularly in the root run due to a combination of factors like high heat in put, slower welding, inability of the welder to control the weld pool, poor joint design/alignment, lack of backing strip when the weld joint is designed for it, local hot spots etc.
When this happens the weld metal hangs out like globules(also called icicles) of different sizes from the back side of the weld. This weld metal solidifies much faster relative to the slow process of solidification in a medium size casting. During this fast solidification process a shrinkage cavity will be created at about the center of the metallic globule with relatively smoother walls. The shrinkage cavity in this case resembles that of a large gas hole in a casting due to faster solidification rate. In a mid size casting the solidification rate is relatively slower and if the feeding/raisering is improper a shrinkage cavity may form with jig jagged walls and appears anything but smooth in the radio-graph.
Best wishes
P V SASTRY

 
 Reply 
 
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
22:41 Feb-22-2012
Re: radiography
In Reply to shankar at 18:54 Feb-21-2012 .

Dear Sir,

Well the classical limits of radiography with Iridium-192 gamma source are something like 25 to 65 mm of steel or equivalent.

But the lower limit was pushed by some people to about 6.35 mm in steel by using slow films and a combination of screens. The upper limit is again pushed to about 75 to 80mm in steel again by using special fluorescent screens, faster films etc. Though I have not shot 6.35 mm myself I was often shooting 9 to 12 mm thicknesses particularly with double film techniques to cover large thickness variations.

Best wishes
P V SASTRY

 
 Reply 
 
balwinder singh
Other,
India, Joined Nov 2011, 16

balwinder singh

Other,
India,
Joined Nov 2011
16
06:39 Feb-23-2012
Re: radiography
In Reply to Rameez at 03:58 Jun-09-2010 .

Dear Sir,

it is burnthrough

 
 Reply 
 
gary
gary
11:26 Feb-23-2012
Re: radiography
In Reply to Rameez at 03:58 Jun-09-2010 .

It's burn through.

 
 Reply 
 
Phil
NDT Inspector, Radiation Safety
BINDT, MIAQP, United Kingdom, Joined Mar 2009, 151

Phil

NDT Inspector, Radiation Safety
BINDT, MIAQP,
United Kingdom,
Joined Mar 2009
151
07:32 Feb-24-2012
Re: radiography
In Reply to Rameez at 03:58 Jun-09-2010 .

Hi

It looks like a burn through but the quality of the image displayed is not as good as it could be.

But from the information given it does seem to indicate that it is a burn through.

Regards

 
 Reply 
 

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