where expertise comes together - since 1996

Web's Largest Portal of Nondestructive Testing (NDT)
Open Access Database (Conference Proceedings, Articles, News), Exhibition, Forum, Network

All Forum Boards
Technical Discussions >
Can anybody explain me for ISO 13847 ?
Career Discussions
Job Offers
Job Seeks
Classified Ads
About NDT.net
Articles & News

1366 views
14:21 Feb-28-2010
Nandesh Kumar A
Can anybody explain me for ISO 13847 ?

One of our code (ISO 13847 ) says the following.

"The total area, when projected radially through the weld, shall not exceed 2% of the projected weld area in the radiograph. The area shall be the length the weld affected by the porosity (with a minimum length of 150 mm ) times the maximum width of the weld."

The above criterion is in order to evaluate porosity on a radiograph. Now I've a uniformly distributed porosity of upto 45 mm length. The total length of the weld is 192 cm (24 inch OD, pipeline )Can anybody explain me (if possible with a sketch) how to proceed with it?

Replies are highly appreciated.

Nandesh Kumar

 
15:09 Mar-01-2010

Nigel Armstrong

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1094
Re: Can anybody explain me for ISO 13847 ? In Reply to Nandesh Kumar A at 14:21 Feb-28-2010 (Opening).

Nandesh

If the weld length affected by porosity is 45mm, this is less than 150mm and so you must use the default 150mm figure. Multiply this by the maximum width of the weld in the affected region and then multiply by 0,02 (2%). Say the weld width is 25mm: 150mm x 25mm x 0,02 = 75 sq mm. Measure and add together all pore diameters in the affected region, multiply the total by pi. If the calcualted figure is less than your previous calculation (75 sq mm in my example) then the area is accpetable. Greater pore area sum total = rejectable.

Hope this helps

 
05:33 Mar-02-2010
Nandesh
Re: Can anybody explain me for ISO 13847 ? In Reply to Nigel Armstrong at 15:09 Mar-01-2010 .

Thanks Nigel...but can ypu please explain me whats the terms " projected radially" and " projected weld area " in my post?
Regards,

 
06:34 Mar-02-2010

Nigel Armstrong

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1094
Re: Can anybody explain me for ISO 13847 ? In Reply to Nandesh at 05:33 Mar-02-2010 .

Nandesh

The use of "projected" radially and weld area is to maintain proportionality with regard to image magnification. If the set-up used has a low ratio between source-to-object distance and material thickness, differential magnification will enlarge a source-side pore more than a film-side pore.

Assuming you used a panoramic exposure on a 24" sch 40 pipe (wt = 0,375") then differential magnification is not a problem you need worry about.

Hope that helps

Nigel

 
13:08 Feb-08-2014
Muhammad
Re: Can anybody explain me for ISO 13847 ? In Reply to Nigel Armstrong at 15:09 Mar-01-2010 .

Sir can you please help me to understand below clause of my project spec.
"The distribution of scattered porosity is such that when projected radially through the weld the total area of porosity exceeds 1% of any 600mm Sq of projected weld metal."
Thanks in advance

 


© NDT.net - The Web's Largest Portal of Nondestructive Testing (NDT) ISSN 1435-4934

Open Access Database, |Conference Proceedings| |Articles| |News| |Exhibition| |Forum| |Professional Network|