Corrosion on Pipe Internal Surface

[cilacap]

Dear all friends,
We have a contract to Built a Boiler Cap. 110 t/h complete with its supporting equipment and pipe lines with a local contractor. We are now in phase constructions and some materials already in site. We had a problem when carbon steel pipes come in site, while we inspected them by visual, mostly pitting corrosion appear on internal pipes surface. We said to pipe supplier, that we rejected many pipes caused of corrosion pitting. However, the supplier could not accept our argument, and judge that conditions were normal, and denied to substitute with other new ones, and . Now, we are in conflict due to we have no standard parameter to judge whether the pipes shall be accepted or rejected. At present I just refer to new conditions means everything is smooth. In accordance with my problem, for to you all, please help me to give advices.

Appreciate for your attention.

Thanks and Regards

 

[metengr]

cilacap;
I have seen and been through this before, unfortunately. If your contract documents do not have specific requirements or instructions for capping pipe/tube for shipment, you are probably out of luck on this one.

I would perform ultrasonic thickness testing of the affected pieces to determine if they can be installed, as is.

 

[EdStainless]

read the specifications carefully. Often there is a workmanship clause. If the piping is not in the 'as manufactured' condition then you have a right to complain, if you have specifications to back you up.

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http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[0707]

In principle I believe that you purchase your pipes under a specification. For instance if your pipe was delivered through an ASTM spec, there is normally a paragraph, which states the acceptable imperfections or defects. “Workmanship, Finish and Appearance” other specs should have similar requirements.

luis

 

[cilacap]

Dear All,

Thank you and appreciate for your responds. I had read ASTM A106, and specifically on sec. 18 about Workmanship, Finish and Appearance. Nevertheless, in my opinion the problem is different. ASTM cites the imperfections caused by workmanship, but in my case, the problem caused by environment pitting corrosion on pipe internal surface. The corrosion attacked on large area of pipe. Cleaning by rotation wire brushing had been done, and the results some pipes be clean and remains pipes corrosion still visible on pipe surface. The specification of pipes mostly is ASTM 106.
Therefore, I am still hoping for your advice more.
Thank you

 

[metengr]

Nevertheless, in my opinion the problem is different. ASTM cites the imperfections caused by workmanship, but in my case, the problem caused by environment pitting corrosion on pipe internal surface.

As I suspected in your OP, you need to specify shipping requirements for delivery to your site. Workmanship is very rarely the issue. If you have none, you have no claims against the supplier. This is unfortunate, but I have been down this road once before, and never again.

 

[0707]

Cilacap

My advice is that you have to argue with your supplier on the basis of the tolerances stated on sec 18 of your ASTM A106.
Surface imperfections that penetrate more than 12,5% of nominal wall thickness or encroach on the minimum wall thickness shall be considered defects

You can compare your pitting corrosion with the tolerances stated on ASTM. If the deep of your pits corrosion is beyond the tolerances you can reject your pipes.

Regards

luis

 

[metengr]

0707;
Unless the purchaser can prove that the pipe was supplied in such condition before it left the mill or warehouse, they don't stand a chance. Shipping is a whole different set of circumstances.

 

[0707]

metengr

Purchaser must fundament his argues in technical positions. If purchaser doesn’t achieve an agreement with the supplier based on the specs, then purchaser must go to a lawyer and put an action in tribunals, which is not good publicity for the supplier.

luis

 

[stanweld]

0707
Beware; the costs of litigation may far exceed any recompense there from.