RE: [MW:12152] RE: 12130] Hi-low into WPS

Thanks so much my friend. Your support is always welcome and appreciated.
 
The bad thing is when the joints are for pipelay and you can not do anything to counterbore the pipes, because even though the ovality is correct in all of the pipes; one of the these with the highest ovality permited can match with that with ovality "zero" and having more offset than permited.

Eduardo Calva

 

---

From: pgoswami@quickclic.net
To: materials-welding@googlegroups.com
CC: eduardocalva@hotmail.com
Subject: [MW:12133] RE: 12130] Hi-low into WPS
Date: Sat, 6 Aug 2011 20:18:45 -0400

Hi Eduardo,

 

See the extracts from API-1104 and DNV-OS-F101 for your reference.Both calls for a control of offset during welding.API calls fro a control during production weld, while DNV diplomatically puts forth this requirement, in Table C-2, clause, 6(a) and 7(e).

 

One good way to tackle the problem would be to counterbore the pipes, to keep the offset to the required minimum.If that's achievable the there's no need for separate PQR's with  different Hi Lo's.

 

Basically a change of hi-lo would alter the penetration profile for single sided FP joints, which is followed  for most of the pipes.Needless to elaborate for excessive high-los the radiographic quality  would suffer.

 

I would think a discussion with the client in line with the requirements of API and DNV spec would be useful

 

Thanks.

 

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Ontario,Canada.

Email-pgoswami@sympatico.ca,

pgoswami@quickclic.net

 

API 1104-

7.2 ALIGNMENT

The alignment of abutting ends shall minimize the offset between surfaces. For pipe ends of the same nominal thickness, the offset should not exceed 1/8 in. (3 mm). Larger variations are permissible provided the variation is caused by variations of the pipe end dimensions within the pipe purchase specification tolerances, and such variations have been distributed essentially uniformly around the circumference of the pipe. Hammering of the pipe to obtain proper lineup should be kept to a minimum.

 

 

 

---

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Eduardo Calva
Sent: Saturday, August 06, 2011 11:22 AM
To: materials-welding@googlegroups.com
Subject: [MW:12130] Hi-low into WPS

Hi dears, could you please tell me if according to API-1104, DNV, etc. the range for hi-low must be indicated in the wps and being a essential variable?
 
A client was asking about qualifying a coupon for minimum hi-low and one for the maximun hi-low in order to have a range qualified, but how does the level of hi-low affect in a welded joint?
 
Also in order to avoid hi-low levels to exceed the range we must to make sure the correct ovality of the pipes.
 
Thanks for your time and help

Eduardo Calva

 

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.