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Seamless pipe ripples.
- Thread starter bob74r
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That looks nasty but maybe the optical effects emphasise the ripple. I wonder what is the cause of that.
All I can see in my copy of A106 (2002) is Dimensions section 16.2.3 - for pipes over 10" diameter gives +/- 1% tolerance of the specified ID, if ordered as ID tolerance pipe.
Hope this helps
All I can see in my copy of A106 (2002) is Dimensions section 16.2.3 - for pipes over 10" diameter gives +/- 1% tolerance of the specified ID, if ordered as ID tolerance pipe.
Hope this helps
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Seamless tubing is the worst tolerance tubing made. If the size of the wall and other features meet tolerance the manufacturer will say that it is in spec. If the wall thickness is smaller than .625 try to use DOM if engineering will allow. If design engineering requires seamless then they must accept the material if it is in spec. The ID could be machined but that will add cost. You could try to deal with a supplier who will send you material specially picked for your application. Purchasing will then balk because the price will not be from the lowest price provider.
I've seen that in thickwall seamless pipe before. It is not really uncommon, but, IMO the lighting in the photograph is exaggerating the appearance.
You are concerned that the uneven surface will corrode faster than a smoother as-rolled surface? I am not sure I understand your concern.
It is not an uncommon condition for heavy wall seamless pipe; it results from the piercing operation. I am unaware of any limits other than the wall thickness requirements, which would suggest to me that it is not a major problem for most uses. If it was a problem, there would be limits in the specification.
rp
You are concerned that the uneven surface will corrode faster than a smoother as-rolled surface? I am not sure I understand your concern.
It is not an uncommon condition for heavy wall seamless pipe; it results from the piercing operation. I am unaware of any limits other than the wall thickness requirements, which would suggest to me that it is not a major problem for most uses. If it was a problem, there would be limits in the specification.
rp
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You never mentioned the wall thickness, so I have no idea if anyone would consider it heavy or not. My comment was that, with thickwall seamless pipe (hot-rolled pierced tubes), this condition is not uncommon. A lot depends on whether the tube came directly off a piercing mill, or if it was run through a roll-reducing mill after the piercing operation. The piercing imperfections would still exist after roll-reduction, but they would be drawn out and you would have a hard time seeing them.
This condition is common enough that the standards would address the issue directly if product that otherwise met the requriements of the standard, but had this condition, was detrimental to the intended service.
I am still unsure about the source of your concern on corrosion.
Also, the shallow-angle lighting such as that used in the photograph necessarily exaggerates surface irregularities. With incident lighting at 90 degrees, I doubt you would even be able to see them in a photograph.
I have seen these irregularities many times in pipe, but I've seen a lot of pipe. Usually, they are "discovered" by someone shining a light down the ID looking for something other than the ID surface condition, but because of the exaggerated appearance, they "raise a flag" on it. I have never seen a steel mill honor a claim for this condition. The fact that the client accepted the material indicates they did not feel it was worth persuing, either.
rp
This condition is common enough that the standards would address the issue directly if product that otherwise met the requriements of the standard, but had this condition, was detrimental to the intended service.
I am still unsure about the source of your concern on corrosion.
Also, the shallow-angle lighting such as that used in the photograph necessarily exaggerates surface irregularities. With incident lighting at 90 degrees, I doubt you would even be able to see them in a photograph.
I have seen these irregularities many times in pipe, but I've seen a lot of pipe. Usually, they are "discovered" by someone shining a light down the ID looking for something other than the ID surface condition, but because of the exaggerated appearance, they "raise a flag" on it. I have never seen a steel mill honor a claim for this condition. The fact that the client accepted the material indicates they did not feel it was worth persuing, either.
rp
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Yes Ive seen a lot of pipe to but never with ripples of this magnitude.
You can claim the picture exaggerates it all you want I've seen and felt this pipe in person (6" STD BTW).
Concern for corrosion?
What happens when you run a fluid down a straight run a pipe with no imperfections,excess penetration on welds or poor fit-ups with major miss alignment? Not a lot.
Now through any of these three into the mix
Excess pen your welds going to corrode so much faster as your fluid has a large plain to resist against. Yes there is code requirements for amount of penetration acceptable in a weld and certain services you can forgot about using a SMAW 6010 completely due to the root profile ( yes this is a dirty rod but compare an STT or GTAW root profile simply for penetration which weld has greater penetration?)
Poor fit up or ripples of this nature well your fluid now suddenly doesn't flow as straight more resistance... what happens when a river hits a large rock?
Same principle instead of a straight steady flow your now creating mini vortexes at each one.
Compare a UT thickness reading on a straight run no ripples pipe to one one with ripples after a year in service. You will see the difference.
All our piping is bought through a 3rd party vendor so weather or not the steel mill wants to honor the claim is the vendors issue not ours (even more so when our contract reads we have the right to reject pipe of this nature)
The only thing that the client accepting this pipe means to me is that once they sign off on it knowing the issue its no longer my concern or future legal problem.
All clients are incredibly smart now a days right?
You can claim the picture exaggerates it all you want I've seen and felt this pipe in person (6" STD BTW).
Concern for corrosion?
What happens when you run a fluid down a straight run a pipe with no imperfections,excess penetration on welds or poor fit-ups with major miss alignment? Not a lot.
Now through any of these three into the mix
Excess pen your welds going to corrode so much faster as your fluid has a large plain to resist against. Yes there is code requirements for amount of penetration acceptable in a weld and certain services you can forgot about using a SMAW 6010 completely due to the root profile ( yes this is a dirty rod but compare an STT or GTAW root profile simply for penetration which weld has greater penetration?)
Poor fit up or ripples of this nature well your fluid now suddenly doesn't flow as straight more resistance... what happens when a river hits a large rock?
Same principle instead of a straight steady flow your now creating mini vortexes at each one.
Compare a UT thickness reading on a straight run no ripples pipe to one one with ripples after a year in service. You will see the difference.
All our piping is bought through a 3rd party vendor so weather or not the steel mill wants to honor the claim is the vendors issue not ours (even more so when our contract reads we have the right to reject pipe of this nature)
The only thing that the client accepting this pipe means to me is that once they sign off on it knowing the issue its no longer my concern or future legal problem.
All clients are incredibly smart now a days right?
It looks as scale left by the die, if 1/64th max, it is normal. sect.II-A allowance, if beyond you can reject the pipe based on the Code.
If you did not invoke the Code section at ordering you maybe jeopardizing your claim.
I have rejected materials based on the Code, then the supplier says: I do not go by the ASME Code but ASTM, then I said: read ASTM and advise.
Most materials meet the same specs.
If you did not invoke the Code section at ordering you maybe jeopardizing your claim.
I have rejected materials based on the Code, then the supplier says: I do not go by the ASME Code but ASTM, then I said: read ASTM and advise.
Most materials meet the same specs.
As previously stated, ASTM A-530 Section 8.0 governs variations in wall thickness for A-106 pipe. If it meets those requirments, it must be accepted (payed for) or it may be exchanged. Since it has been fabricated into spools by others, you will be stuck with the added costs of replacement umless your contract somehow permits otherwise. It does not preclude you from prohibiting its use on a particular project or prohibiting the pipe manufacturer thereof on future orders.
Assuming a mild corrosive service, I would be less concerned with corrosion than with pumping efficiency [from your statement above "more resistance"].
Assuming a mild corrosive service, I would be less concerned with corrosion than with pumping efficiency [from your statement above "more resistance"].
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