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Technical Discussions
Tom
Tom
09:50 Aug-14-2007
Elliptical Shots

Does anyone know a general rule of thumb as to how much of an offset you should use to radiograph a 2" joint using an elliptical exposure?


 
 Reply 
 
Dent
Consultant, NDE Manager NDELevel III/3
NDT Consultant, Canada, Joined Nov 1998, 252

Dent

Consultant, NDE Manager NDELevel III/3
NDT Consultant,
Canada,
Joined Nov 1998
252
05:10 Aug-14-2007
Re: Elliptical Shots
----------- Start Original Message -----------
: Does anyone know a general rule of thumb as to how much of an offset you should use to radiograph a 2" joint using an elliptical exposure?
------------ End Original Message ------------

15 Deg should work.


 
 Reply 
 
DJ Kallhof
DJ Kallhof
08:38 Aug-14-2007
Re: Elliptical Shots
----------- Start Original Message -----------
: : Does anyone know a general rule of thumb as to how much of an offset you should use to radiograph a 2" joint using an elliptical exposure?
: 15 Deg should work.
------------ End Original Message ------------

7 : 1 ratio has worked well for me in the past. Back off 14" and offset 2" or 21" and offset 3". You get the idea. The only thing that can make it tricky is excessive weld build up of the root or crown. Take a technique and adjust accordingly.



 
 Reply 
 
chris s
chris s
00:44 Aug-15-2007
Re: Elliptical Shots
----------- Start Original Message -----------
: : : Does anyone know a general rule of thumb as to how much of an offset you should use to radiograph a 2" joint using an elliptical exposure?
: : 15 Deg should work.
: 7 : 1 ratio has worked well for me in the past. Back off 14" and offset 2" or 21" and offset 3". You get the idea. The only thing that can make it tricky is excessive weld build up of the root or crown. Take a technique and adjust accordingly.
------------ End Original Message ------------

i use the 7:1 ratio also, works fine. until you get into heavy wall


 
 Reply 
 
G.Madhesan
G.Madhesan
01:44 Aug-22-2007
Re: Elliptical Shots
As said by Mr.Dent You can use a 7:1 technique but you have to consider the thickness of the pipe because the root will vary deponds upon the wall thick.


 
 Reply 
 

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