Pitted appearance on 8" xxs steel pipe 5

[jlrariel]

I recently purchased some 8" double extra strong Pipe.
the pipe has a pitted appearance which the mill tells me is normal. There is no corrosion evident so what would make the pipe appear pitted? There is a clear laquer protective coating over the pipe which does not seem to be the culprit. The mill states the .875 wall requires them to run a rough process. What does that mean?

Cynthia Brugger, CPM
Erection & Welding Contractors

 

[chicopee]

How is the pitting distributed in the pipe?

 

[metengr]

Are you confusing surface pits (from corrosion) with excessive surface roughness from typical hot working conditions to produce pipe?

 

[jlrariel]

The pitting is evenly distributed throughout the pipe, interior and exterior. There is no evidence of corrosion at all. It is my understanding that when you specify grade A53 in pipe that once you exceed a certain schedule that it is hot finished which produces a rough surface. We cut through the pipe diagonally to examine for rust and found none... I was looking for the literature that states the process which forms the surface. I never had to order anything like this so I was totally unaware of how the surface would look. I want to demonstrate that the pipe is not defective but rather looks like that because of the process.

 

[jlrariel]

The pitting is evenly distributed throughout the pipe, interior and exterior. There is no evidence of corrosion at all. It is my understanding that when you specify grade A53 in pipe that once you exceed a certain schedule that it is hot finished which produces a rough surface. We cut through the pipe diagonally to examine for rust and found none... I was looking for the literature that states the process which forms the surface. I never had to order anything like this so I was totally unaware of how the surface would look. I want to demonstrate that the pipe is not defective but rather looks like that because of the process.

 

[brandonb73]

You need to read the spec for A53 pipe. It will tell you what the acceptable finish and appearance is.

If it does note meet it, you are well within your right to refuse it.

 

[BigInch]

Picture?

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[jlrariel]

Picture of 8" pipe

 

[metengr]

Typical mill scale that was embedded during fabrication and subequently removed.

 

[jlrariel]

I had the hardest time finding it. I am from the East Coast and searched all of the US (at least I thought I did) I could only find it in Germany through a West Coast distributor
never the less, Will SSPC SP10 w/build up primer make any difference?

Cynthia

 

[vesselfab]

IN STOCK A-53-B/A106-B/API-5L
US domestic

132.00 a foot

ALWAYS call the Texas Gulf Coast when looking for pipe

 

[jlrariel]

Is the surface smooth? What is your process?

 

[vesselfab]

smoother than pictures given

black laquered paint for protection

from Northstar Mill V&M

Not mine....my distributor

You could call northstar for a picture sample

 

[jlrariel]

The whole concern here from the Arch is the visual appearance. I tried to explain to the design team that this pipe does not come smooth period. I have explained it but someone told them they could get that pipe smooth. Maybe smoother than what I have but not smooth like schd 40. The wall thickness is .875

The whole issue is not integrity but rather appearance.
I wish someone could aol me with a direction or a industry reference to the process

 

[vesselfab]

well pehaps you can use a similar size (not pipe sizes) in drawn mechanical tubing.

 

[jlrariel]

I tried to substitute that first before I bought the 8" pipe. For availability reasons they said no, pipe A53 XXS. Now the burden is on me because they didn't realize what they were specifying

 

[racookpe1978]

Photo doesn't look right to me: As if they (the seller!) had some very, very rusted and pitted pipe in the back of the yard, cleaned it with grinding wheel and a wire brush, then loaded it on the truck.

The "square-edged" and "rectangular" pits are odd - never seen them in power piping (steam and feed water) like that. I'd follow your instincts on this one - which is why they are there as a survival trait urging "Caution! There's a tiger behind that bush." - and require the seller show you that that level of pits meets the "manufactored in good order and of high quality" generic material spec.

 

[chicopee]

I think metengr is partly right about the mill scale and racookpe1978 partly right about pits developing in the back yard.

 

[jlrariel]

Thank you all for your input and advise.