mechanical 1

[Wisam Hashim]

hi every body
Iam working in pipeline construction company. I already made purchase order for welded pipes 42 inch api 5L X60 ,14.3 mm wall thickness but the vendor who supplied the pipes make the purchase order for the plates (raw material of pipes) with wall thickness 13.8mm and when I discussed with him about this variation he said this is accepted according to the tolerance in api 5l therefore could any person clarify that the thickness tolerance in API 5L concern the variation in thickness during manufacturing process or it can be consider as permision for vendor to provide the plates (raw materials for lsaw pipes) with a thickness within the tolerance

 

[SnTMan]

Jesus, read the specifications...

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Wisam Hashim]

thank you SnTMan
the specification did not indicate any information about the plate delivered it just talking about the pipe

 

[Geoff13]

Tolerances are at the time of shipping / receiving. I don't think you can complain yet.

Your vendor is taking a risk. The plate will have its own under-tolerance (typically 0.3 mm) so it seems very unwise to use all the pipe 0.5 mm undertolerance when they ordered the plate. The plate mill will ship plates up to 0.3 mm under-tolerance (i.e. 13.5 mm thick), as these are acceptable, and the vendor will have to buy them as they meet spec. Thus your vendor will a cost incentive to use them in your pipes. Perhaps your vendor can explain how they will prevent under-tolerance plate making it into your pipes.

You should have a receiving checklist that checks thickness in sufficient locations. This may be more locations than any standard checklist you normally use due to the unusual vendor plate order, and should include UT thickness checks along the pipe length.

 

[mk3223]

Simply, the vendor's material of pipe was not complied with the API 5L Spec in the PO.
The question, where is the agreement of the thickness change in the PO?

 

[Wisam Hashim]

dear mk3223
is there any paragraph in API 5L taking about the P.O agreement by employer or taking about the agreement due to thickness change

 

[JStephen]

Typically, plate tolerances are fairly tight, pipe tolerances can be considerably larger.
It is conceivable that you could order under-thickness plate, fabricate into pipe, and still meet a pipe tolerance.
However, in our tank work, there is a separate requirement that you're not allowed to order less than the required thickness.
With that in mind, you need to refer to the thickness requirements of the code being used to see exactly what it does and does not specify. That may involve paying actual money to get a copy of it, rather than asking on a forum.

 

[LittleInch]

Geoff,

I don't know where you're getting 0.5mm from - the standard wall thickness tolerance in API 5L at that size is +/- 1.5mm.

Now normally the buyer adds his own spec on top to reduce this or modifies it in the PO. Wisham - did you have an additional specification?

This seems pretty shady to start lower as a nominal, but then if you don't spec it out better than 5L then you get what you pay for - in this case thinner pipe than you thought you were getting.

I sure wouldn't use this mill or supplier ever again, but then I wouldn't rely on a base 5L spec either.

I would also hire the most annoying inspector I could find and tell them to check every last thing they can, twice. If there are this brazen then who knows what the actual steel is made from..... or its strength.





Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Geoff13]

Oops. Looked too quick at Table 11, and found the wrong row.

It's sort of helpful that 5L allows a larger tolerance, but still not a vendor I'd want to buy from.

 

[SnTMan]

I don't know API 5L from sic'em, but the way it normally work is, is if it is not prohibited, it is permitted.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[KevinNZ]

API 5L not only has a tolerance for wall thickness, there is also a tolerance on the weight, which means the pipe can not be thin everywhere.

Thickness tolerance on x60 42" is -8% but weight tolerance is -3.5% or better.

 

[nirmalbose]

Dear all

we need VRF design and draft details.

regards
Nirmal

 

[SnTMan]

And that would be what, exactly? BTW it is considered impolite to add an unrelated question to (hijack) an existing thread.

nirmalbose, please start a new thread of your very own with enough detail so people know what you are talking about.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand