Prasad et all,
Selective absorption is the basic principle of radiography and it depends on a given material's density, A No., thickness etc. Under similar conditions of source energy and not so much the intensity, let me point out, low thickness will offer less absorption and more transmission - making the film dark and and a radiographic image with poor contrast making it difficult to distinguish a discontinuity from sound material. (Allow me to repeat, sound material and discontinuities respond differently to a passing radiation.) This will defy the very purpose of a good radiograph. Gamma sources have definite energy levels and can not be controlled, so to say, for any variation vis-a-vis thickness. With x-rays, you have facility to control energy (kV control) and mA control for intensity . Exposure time has, of course, its own role to play. This makes use of x-rays more versatile - you can change energy as per thickness, and intensity and exposure time as per optical density requirements.
From: dilintas <dilintas@gmail.com>
To: Meghanadh K <materials-welding@googlegroups.com>
Sent: Thursday, 17 November 2016 11:25 PM
Subject: Re: [MW:25730] Why xray are use for lower thickness
Regarding your point no2, you will never find such a recommendation in the Code
Sent from my Samsung Galaxy smartphone.
-------- Original message --------
From: Prasad Rode <purode333@gmail.com>
Date: 16/11/2016 15:27 (GMT+02:00)
To: materials-welding@googlegroups.com
Subject: Re: [MW:25723] Why xray are use for lower thickness
Dear Sir's,
I agree that , we get better quality of radiograph in xray.
I only want to discussed that,
1) If we want to talk about radiography quality, then if required IQI is visible, then we can say that minimum defects is visible as required IQI is visible.
Code also says that radiographs quality or acceptance, depends on visibility of require IQI.
2) my another point is that, in which section or code, it is mention, that below particular thickness of material, xray to be use and above that thickness, gamma is allowed. So that we can insist contractor to do the same.
I only want to discussed that,
1) If we want to talk about radiography quality, then if required IQI is visible, then we can say that minimum defects is visible as required IQI is visible.
Code also says that radiographs quality or acceptance, depends on visibility of require IQI.
2) my another point is that, in which section or code, it is mention, that below particular thickness of material, xray to be use and above that thickness, gamma is allowed. So that we can insist contractor to do the same.
Thanks for response.
Expecting the same.
Expecting the same.
Regards
Prasad
Prasad
On Nov 16, 2016 17:39, "Kannayeram Gnanapandithan" <kgpandithan@gmail.com> wrote:
-- no, X-ray is the best one--THANKS & BEST REGARDS,KG.PANDITHAN, IWE, AWS-CWI, CSWIP 3.1,CONSULTANT-WELDING & QUALITYMobile no: +919940739349On Wed, Nov 16, 2016 at 11:48 AM, Prasad Rode <purode333@gmail.com> wrote:
Dear prem and George sir,
Thanks for reply.
I want to ask that if I use the high sourse ir192 and increase the exposure time i.e. time as required by calculation, can I get the good radiographs and using iqi of din standard.
Our thickness of pipe is below 4mm.
We required genuine and technical reason to insist to contractor.
Requesting for response.
Regards
Prasad
--
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