New 316L tube internal pitting 4

[newerbee]

Hi,

we want to order new 316L SS tubes based on ASTM A269. However, we have been made aware that small diameter tubes may have suffered internal contamination and pitting due to manufacturing process resulting from insufficient cleaning (especially for small dia tubes) and this is accepted "normal".

I strongly find this unacceptable to have a pitted or contaminated brand new tubes.

what is the industry experience? would you accept this? has anyone come across something like that?

thanks.

 

[EdStainless]

It may not be uncommon but it is completely unacceptable.
The ID should be smooth and clean, period.
We have some customers with special ID requirements (surface finish or special cleaning procedures) but for normal service that shouldn't be required.
If you get tubing in that has visible contamination reject it, it fails the workmanship clause.
Now, the ID may be rough, but that is another issue. Ask to see samples of similar product.

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P.E. Metallurgy, Plymouth Tube

 

[metengr]

You bet this is unacceptable. I had experienced a similar situation about 10 years ago with a highly reputable condenser tube supplier. It was very poor QC during fabrication and we had them at the Plant to discuss the issue. All the supplier could say was that their backstop failed and defective tubes were crated with acceptable tubes. We had them pay for inspection, removal and replacement of defective condenser tubes.

 

[moltenmetal]

Stop buying Chinese seamless tubes, or seamless tubes in general. Problem solved.

 

[EdStainless]

All of our ID surface critical applications require welded and cold drawn tubes ( and as a bonus the ID is in the center of the tube).

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P.E. Metallurgy, Plymouth Tube

 

[metengr]

Unfortunately, from my experience it was a tubing manufacturer in the midwest US and that is all I will say about it.

 

[EdStainless]

That narrows it down to 5 or 6 ......

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P.E. Metallurgy, Plymouth Tube