EFW vs. SAW 1

[ngot]

Hi

We have specified 42” and 34” pipe in API 5L Gr. B EFW, with HIC resistant test complying with NACE MR0103, TM 02-84 and TM-01-77. The pipe is in a service where wet H2S might appear.
One of our supplier have offered us 42” and 34” API 5L Gr. B, PSL 2, SAW, NACE MR0175.
The wall thickness is 12.7 mm, and the weld is 100% X-rayed.

We do not have any experience with SAW, will it give any problems, do we need extra requirements, compared to EFW?
Will the change in NACE standard give any problems??

Thanks
NGOT

 

[pennpiper]

I am confused by your term EFW. Is this the same as ERW? If so see the following:

The information was found on the pipingdesigners.com website Forum and submitted by "ACD"
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ERW Pipe is a cheaper product due to low manufacturing cost but has limited application in terms of size, grade and end use.


ERW - Electric Resistance Welded
For pipes or tubes size 4 inch (10.2mm) OD and below, strip is fed into a set of forming rolls which consists of horizontal and vertical rollers so placed as to gradually from the flat strip in to a tube which is then allowed to pass the welding electrodes. The electrodes are copper disks connected to the secondary of a revolving transformer assembly.

The copper disk electrodes make contact on each side of the seam and temperature is raised to the welding point. Outside flash is removed by a cutting tool as the tube leaves the electrodes, inside flash is removed either by an air hammer or by passing a mandnel through the welded tube after the tube has been cooled. This is termed as Electric Resistance welded or ERW tube/pipe. If this ERW is being drawn further to get desired size of tubes or pipes, in cold condition is called as Cold Drawn welded or CDW.

SAW - Submerged Arc Welded
This process is used for pipes from 24" to 36" i.e 610mm to 914mm OD. Flat plate is first pressed into U and later O shape. The O shape is placed in an automatic welder and backed up on the inside by a water cooled copper shoe. Two electrodes in close proximity and used. The electrodes are not in actual contact with the pipe. The current passes from on electrode through a granular flux and across the gap in the pipe to the second electrode. The high temperature of the arc heats the edges of the plate, a welding rod placed just over the seam is thereby melted and metal is deposited in the groove. After the outside weld has been made, the pipe is conveyed to an inside welder where a similar operation is carried on, except that no backup shoe is need.
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This and the other comments on this subject can be found by doing a search on ERW/SAW on the pipingdesigners.com website.
The pipingdesigners.com website also offers many other answers and suggestions on a wide range of subjects.
Check it out.
PennPiper

 

[ngot]

EFW and ERW are not the same.
EFW is Electric Fusion Welding, a welding process without filler.

Thanks for the link, I will see if it will give my something.

 

[stanweld]

The longitudinal weld seams of large diameter API 5L pipe are most often welded with the submerged arc process. I do not unerstand your concerns. Electric Fusion Welded pipe can be made with or without filler metal.

 

[metengr]

EFW stands for electric flash welded pipe. Here is some background information on EFW pipe.

http://www.kiefner.com/ERW.PDF

I also agree with stanweld on this issue.

 

[NozzleTwister]

Metengr,

That's pretty confusing since electric fusion welded pipe is also called EFW, for example ASTM A671 & A672.

NozzleTwister
Houston, Texas

 

[metengr]

Yes, I came to the same conclusion, which is the reason why referenced the paper. My guess is that the EFW nomenclature for electric fusion welded pipe was adopted after the original process of making seamed pipe using the flash welding process (electric resistance heat + pressure) became less common. Electric fusion welding wasn’t accepted by the ASME Boiler Code committee until after the 1940’s.

Also, EFW (electric-fusion-welded) pipe in terms of ferrous material specifications under ASME implies filler metal added (SA-691 and SA-671)

 

[stanweld]

ngot,
I would be more concerned with the fact that you are contemplating purchasing the pipe without the HIC resistance testing or do you plan to perform such testing after purchase. If so "let the buyer beware". The chance of passing should be considered remote.

 

[25358]

What are the diferent uses of spiral welded pipe and longitudinal pipe?

 

[stanweld]

Both have been and are currently being used in gas and liquid hydrocarbon transportation.